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Mental MathGrade 10 Essential Mathematics2015M a ni t o b a E d u c a t i o n a n d A d v a n c e d L e a r nin g

Manitoba Education and Advanced Learning Cataloguing in Publication DataMental math [electronic resource] : grade 10 essential mathematicsISBN: 978-0-7711-6074-51. Mathematics—Study and teaching (Secondary)—Manitoba.2. Mental arithmetic—Study and teaching (Secondary)—Manitoba.I. Manitoba. Manitoba Education and Advanced Learning.510.712Copyright 2015, the Government of Manitoba, represented by the Ministerof Education and Advanced Learning.Manitoba Education and Advanced LearningSchool Programs DivisionWinnipeg, Manitoba, CanadaEvery effort has been made to acknowledge original sources and to complywith copyright law. If cases are identified where this has not been done, pleasenotify Manitoba Education and Advanced Learning. Errors or omissions willbe corrected in a future edition. Sincere thanks to the authors, artists, andpublishers who allowed their original material to be used.All images found in this document are copyright protected and should notbe extracted, accessed, or reproduced for any purpose other than for theirintended educational use in this document.Schools are encouraged to share this document with parents, guardians, andcommunities, as appropriate.Any websites referenced in this document are subject to change. Educatorsare advised to preview and evaluate websites and online resources beforerecommending them for student use.Print copies of this resource can be purchased from the ManitobaLearning Resource Centre (formerly the Manitoba Text Book Bureau)(stock number 80703). Order online at www.mtbb.mb.ca .This resource is also available on the Manitoba Education and AdvancedLearning website at www.edu.gov.mb.ca/k12/cur/math/supports.html .Disponible en français.Available in alternate formats upon request.

Contents1IntroductionWhy Mental Mathematics3Strategies4Document Features4Methodology5Assessment6Reproducible Sheets1Examples of Strategies1Mental Math Questions by Unit1Unit A: Gross Pay, Time Cards, and PercentsUnit B: Net PayUnit C: MeasurementUnit D: GeometryUnit E: Angles and Parallel and Perpendicular LinesUnit F: Consumer DecisionsUnit G: TrigonometryUnit H: TransformationsContentsiii

Introduction

IntroductionThis document is a complement to the Grade 10 Essential Mathematicscurriculum and is intended to help students develop strategies that allowthem to perform mental calculations.Why Mental Mathematics?Mental mathematics and estimation is one of the seven processes of themathematics curriculum.“Mental mathematics is a combination of cognitive strategies that enhanceflexible thinking and number sense. It involves using strategies to performmental calculations.Mental mathematics enables students to determine answers without paperand pencil. It improves computational fluency by developing efficiency,accuracy, and flexibility in reasoning and calculating” (Manitoba Education andAdvanced Learning, p. 9).It is used by individuals in their daily lives at home and at work. Mentalcalculation requires students to call on their knowledge of numbers andmathematical operations. It not only calls on memory but helps improve it aswell.Mental calculation is at the root of the estimation process. It allows us todetermine whether results obtained with a calculator are reasonable.“Estimation is used for determining approximate values or quantities,usually by referring to benchmarks or referents, or for determining thereasonableness of calculated values. Estimation is also used to makemathematical judgments and to develop useful, efficient strategies for dealingwith situations in daily life” (Manitoba Education and Advanced Learning, p. 9).Mental calculation is an important way of developing number sense andacquiring a better understanding of place value and mathematical operations.Students who have experience with mental math develop the ability to workwith numbers. Mental calculation can be used to prepare for written workby providing an approximate answer to a problem. Using certain mentalcalculation strategies can eliminate some steps in written calculations andhelp simplify the process. In short, mental calculation skills are at the heart ofnumeracy.Introduction3

Mental calculation is used almost daily in life. We often have to do quickmental calculations at times when we do not have paper, a pencil, or acalculator handy. Mental calculation is therefore a very practical skill.Teachers should provide opportunities for their students to use mental mathand estimation on a daily basis. They should encourage their students to findexamples of the usefulness of mental calculation in their lives, such as whenshopping, doing home renovations, estimating mileage, or working at theirjobs.StrategiesTeachers should promote a variety of mental mathematics strategies. Theyare encouraged to make students aware of the strategies described in theStrategies section of this document. The strategies that are most effectivefor mental calculation are often not the same strategies that are mosteffective for written calculation. Most students are able to develop strongmental calculation techniques, but often need help in doing so. Studentsmay discover and use some mental calculation techniques by themselvesbut need to be taught other techniques to increase their mental calculationeffectiveness. Regular mental calculation activities should be included in allmathematics curricula at all grade levels.Document FeaturesThe document includes three main sections: this introduction, a sectiondescribing strategies, and a series of mental mathematics questions organizedby units.The teacher will find mental mathematics questions relating to a specific unitof Grade 10 Essential Mathematics as written in Grades 9 to 12 Mathematics:Manitoba Curriculum Framework of Outcomes. This document follows the orderof units as given in Grade 10 Essential Mathematics: A Course for IndependentStudy. The Mental Math: Grade 10 Essential Mathematics document consists ofeight (8) units:Unit4Number of PagesA: Gross Pay, Time Cards, and Percents8B: Net Pay10C: Measurement11D: Geometry9E: Angles and Parallel and Perpendicular Lines10F: Consumer Decisions8G: Trigonometry9H: Transformations7Mental Math: Grade 10 Essential Mathematics

The units may be taught in a different order as determined by the teacher.Every unit consists of several pages of mental math questions. Each page hasquestions that correspond to the Brain Power questions found in the learningactivities of the Independent Study Option (ISO) course.The number of individual mental math pages for each unit corresponds to thenumber of learning activities given for the unit in the ISO course. The unitof study is identified on each page. The questions on each page are dividedinto three different categories: five (5) general or review questions; three (3)questions related to the unit of study; and two (2) blanks for teachers to inserttheir own questions.The answers to the questions are provided in the column on the extremeright-hand side of each page. Sometimes students are asked to provide theone right answer and at other times they are to provide an estimate where arange of values would be correct.Teachers may want to prepare additional questions to better meet the needs oftheir students. A section at the bottom of each page entitled Other Questionshas been set aside for this purpose. A blank template is also provided in asection titled Reproducible Sheets. Teachers may use it to prepare additionalquestion sheets.A file in Word format is available in the Mathematics Group on theMAPLE (Manitoba Professional Learning Environment) site at www.maple4teachers.ca . The Word file does not contain the Strategiessection of this document but it does contain the section with the MentalMath Questions by Unit. It is provided to enable teachers to add or modifyquestions to suit the needs of their students.Immediately following this introduction is a section describing mentalcalculation strategies along with examples. Some students may already havean inventory of strategies that they can apply; others may not. Teachers canuse the strategies information given in this document to help students expandtheir strategy knowledge.Introduction5

MethodologyGiven their usefulness, mental calculation exercises should be short and donefrequently.They should be short because they require sustained concentration. Forexample, the first five minutes or so of math class could be devoted to mentalcalculation exercises. This practice would also serve as a warm-up to theday’s lesson. In addition, although mental calculation should be done withina certain period of time, it is preferable not to emphasize speed. Althoughspeed is a factor, it is not a primary goal. It is obviously important to ensurethat time spent on mental mathematics activities does not infringe on thetime needed for instruction and other learning activities.Establishing routines in the classroom also encourages students to get to workquickly at the beginning of each class. Teachers could establish a process suchas the following:QQQQQQQQQQAs soon as students arrive at the beginning of the class, they can take out asheet of paper and write down the numbers 1 to 10 if there are 10 questions.The teacher can project a mental math page, present questions orally, ordistribute a page with written questions.The students are given time to answer the questions.If students are unable to find an answer to a specific question, they couldleave an empty space on that question and go on to the next question. Thegoal is accuracy and the development of a bank of effective strategies.The teacher should, on occasion, spend time discussing various strategiesused by the students for one or more of the questions.To ensure students gain confidence with a new strategy, it is important thatthey are given adequate opportunity to practice it. It is up to the teacher toprovide an adequate number of exercises or problems to ensure that studentsare able to use the new strategies.6Mental Math: Grade 10 Essential Mathematics

AssessmentPrimarily, mental calculation exercises are used as assessment for learning.Mental calculation exercises should be done in a classroom environment inwhich students feel comfortable taking risks without being penalized whenthey make mistakes. However, teachers should ask students to do a selfevaluation by identifying the questions they had the most difficulty with orthose they did not answer correctly. Periodically, teachers may choose to usethe mental mathematics questions as assessment of learning by asking themto explain the strategy they used for a specific question or questions.Mental calculation can allow students an opportunity to develop a betterunderstanding of some mathematical concepts. Consequently, mentalcalculation activities should include periods for thought and discussion.During these periods, the teacher should encourage students toQQQQQQsuggest a variety of possible correct solutions to the same problemexplain the different methods used to come to the correct answer and theireffectivenessexplain the thought process that led to an incorrect answerThis type of discussion is very important in learning mental calculationstrategies, because it is an effective way for students to present their thinking.Questioning, reflecting, and discussing, which are integral to the activitiesof mental calculation, are excellent ways of communicating mathematicalideas. This communication requires that students be clear and concise whenexplaining their thinking to others. It is often when students describe thestrategy they used to solve questions that other students discover a newtechnique. These exchanges about the strategies as well as the results willallow the teacher to identify the difficulties encountered by some students.Subsequently, the teacher can help students discover new, relevant, useful,and important strategies.Enjoy the mental mathematics experience!Introduction7

Notes8Mental Math: Grade 10 Essential Mathematics

ReproducibleSheets

Mental MathGrade 10 Essential Mathematics (20S)Unit:General Questions1.2.3.4.5.Unit Questions6.7.8.Other Questions9.10.Answers

Mental MathGrade 10 Essential Mathematics (20S)Unit:General or Unit Questions1.2.3.4.5.6.7.8.9.10.Other Questions11.12.Answers

Examples ofStrategies

Mental MathGrade 10 Essential Mathematics (20S)Sample StrategiesS–1Begin adding from the leftWhen you do additions using paperand pencil, you usually start from theright and work toward the left.To do additions in your head, start from the left.AA1246 3840 30 706 8 1470 14 8420 10 3025.6 13.75 3 8330 8 110 39.36 7310 10 1 and 10

Mental MathGrade 10 Essential Mathematics (20S)Sample StrategiesBreak down numbers and add their partsHere’s another way of doingadditions in your head.63 28Break down the numbers, then add their parts.AA163 2863 20 883 891315 200 70 62315 276515 70 6585 6591S–2

Mental MathGrade 10 Essential Mathematics (20S)S–3Sample StrategiesFinding compatible numbersCompatible numbers are pairs of numbers that are easy to add inyour head.The following are examples of compatible numbers:8614220The sum equals 100AA12380The sum equals 600Find the pairs of compatible numbers that addup to 300.140851601182177321518283140 160118 182215 85217 83Find the pairs of compatible numbers that addup to 800.250175567333440467625550360250 550333 467625 175440 360

Mental MathGrade 10 Essential Mathematics (20S)Sample StrategiesS–4Create your own compatible numbersSometimes it is easier to do additions in your head by creatingyour own compatible numbers and adjusting the total.A1650 375650 350 251000 251025A1250 750 321250 7532000 32003

Mental MathGrade 10 Essential Mathematics (20S)Sample StrategiesS–5Subtract starting from the leftHere’s a technique that works wellwhen doing subtractions that do notrequire grouping.To do subtractions in your head, start from the left andthink of your answer one part at a time.A1400 300 100468– 32360 20 408 3 5100 40 5 145A29000 6000 3000500 200 3009514– 620314 3 113000 300 11 3311

Mental MathGrade 10 Essential Mathematics (20S)Sample StrategiesS–6Subtract one part at a timeWhen you do a subtraction that requires a grouping,subtract one part at a time.A1132– 59132 – 50 8282 – 9 73Check your answer by adding the following in your head:73 59 120 12 132A6.25 – 3 3.2526.25– 3.153.25 – 0.15 3.10Don’t forget to check your answer doing amental addition.

Mental MathGrade 10 Essential Mathematics (20S)Sample StrategiesS–7Balance a subtraction with whole numbersWhen you add the same number to the two elements of asubtraction, the difference between the two does not change.By adding to both elements, you balance the subtraction.That makes it easier to find the answer in your head.AA1276– 28660– 18576 2 7828 2 3078 – 30 48660 15 675185 15 200675 – 200 475

Mental MathGrade 10 Essential Mathematics (20S)Sample StrategiesS–8Balance a subtraction with decimal numbersWhen you add the same number tothe two elements of a subtraction,the difference between the twodoes not change.Adding to both elements balances the subtraction.That makes it easier to find the answer in your head.AA124.32– 1.9523.62– 15.894.32 0.05 4.371.95 0.05 24.37 – 2 2.3723.62 0.11 23.7315.89 0.11 1623.73 – 16 7.73Remember that you have to make sure the second element (notthe first) becomes a number that is easy to subtract.

Mental MathGrade 10 Essential Mathematics (20S)S–9Sample StrategiesMultiply starting from the leftIt is easier to multiply in your head when you breakdown a number and multiply starting from the left.Add in your head as you multiply each part.A1600 4 2400635 430 4 1205 4 202400 120 20 2540A500 3 15002528 320 3 608 3 241500 60 24 1584

Mental MathGrade 10 Essential Mathematics (20S)S–10Sample StrategiesCut and paste the zerosIn multiplication, whenone factor is multiplied by10, the result is alsomultiplied by 10.6 42460 424010Knowing this concept, you can easily multiplyby 10 in your head by following these steps:1. Cut all the zeros at the end.2. Multiply the remaining numbers.3. Paste all the zeros back.AA1213 706000 120013 7 919106 12 727,200,000

Mental MathGrade 10 Essential Mathematics (20S)Sample StrategiesCut and paste the zerosTo mentally divide numbers that endin zero, follow these steps:1. Cut all the zeros at the end.2. Do the division.3. Paste the zeros back.A12400 624 6 4400Check the answer by multiplying: 6 400 2400A245,000 15Check: 15 3000 45,00045 15 33000S–11

Mental MathGrade 10 Essential Mathematics (20S)Sample StrategiesS–12Cut the zeros in dividend and divisorWhen dividing the dividend and divisorin a division by the same amount, thequotient does not change.800 2080 240Knowing this concept will help you do the divisionin your head more easily when the dividend andthe divisor both end in zero.All you have to do is divide both the dividend anddivisor by the same value, 10.AA126300 904,500,000 500630 97045,000 59000

Mental MathGrade 10 Essential Mathematics (20S)Sample StrategiesS–13Work with pricesThe sale price of items is often alittle less than an even number ofdollars.To work with prices in your head, round off to thenearest dollar. Then, do the calculation required bythe problem and adjust your answer.A1 16.65 2.99 16.65 3 19.65 19.65 – 1 19.64A6 20 1202 19.98 66 2 12 120 – 12 119.88

Mental MathGrade 10 Essential Mathematics (20S)S–14Sample StrategiesCheck your changeWhen you buy something, it isimportant to check that the amount ofchange returned to you is correct.There is an easier way than subtracting in your head:add to the purchase price.A1You buy a CD for 14.35 with a 20 bill. How muchchange should you get back?50 Add starting from 14.35 19.50 50 20.00 14.35 5 19.35 19.35 15 19.50 5 5 15 50 5.6515 A2You buy a watch for 74.15 with a 100 bill. Howmuch change should you get back?Add starting from 74.15 99.50 50 100.00 94.15 5.00 99.15 74.15 20.00 94.15 20 5 99.15 35 99.5035 50 20 5 35 50 25.85

Mental MathGrade 10 Essential Mathematics (20S)Sample StrategiesS–15Find the time differenceMental math calculation is useful tofind how much time is left beforean event.To find the difference between two given times,add by steps.A1If it is 8:27 a.m., how long do you have to wait beforelunch at noon?TO 12:00 noon3 HOURS8:27 a.m. to 8:30 a.m.3 MINUTESTO 9:00 a.m.30 MINUTESA23 HOURS33 MINUTESIf it is 9:50 a.m., how much time is there before 8:15 p.m.?TO 8:15 p.m.15 MINUTES9:50 a.m. to 10:00 a.m.10 MINUTESTO 8:00 p.m.10 HOURS10 HOURS25 MINUTES

Mental MathQuestions by UnitGrade 10 Essential Mathematics

Mental MathGrade 10 Essential Mathematics (20S)A–1Unit A: Gross Pay, Time Cards, and PercentsGeneral Questions1. You walk 2 km north, then you turn around and walk 5 km south.How many km and in what direction are you from your starting point?34of a pizza and Nick eats of a pizza, how many pizzas55do they have to order so that both can eat as much as they like?2. If Evan eats3. Write6in simplest terms.2Answers3 km to thesouth23 314. Knowing 50% of 680 is 340, evaluate 25% of 680.1705. If you buy a shirt for 8 and jeans for 32, how much do you spendaltogether (before taxes)? 40Unit Questions6. Convert 47.5% into a decimal number.0.4757. Change 17% to a decimal number.0.178. Write the decimal form of 4.32%.Other Questions9.10.0.0432

Mental MathGrade 10 Essential Mathematics (20S)A–2Unit A: Gross Pay, Time Cards, and PercentsGeneral QuestionsAnswers1. Rank the numbers highest to lowest: 0.5, 0.05, 0.3, 0.09, 0.252. Evaluate the following: 2 - 3 6 2 - 5 40.50, 0.30, 0.25,0.09, 0.05-93. Solve for i: 4i 3 1534. Is an angle that measures 140 acute, right, obtuse, straight, or reflex?obtuse5. Write the next two numbers in the pattern: 1, 2, 4, 8,16, 32,Unit Questions6. Convert 0.56 to a percent.56%7. Write the percent form of the number 0.034.3.4%8. Change 0.0025 to percent form.0.25%Other Questions9.10.

Mental MathGrade 10 Essential Mathematics (20S)A–3Unit A: Gross Pay, Time Cards, and PercentsGeneral Questions1. A volleyball team trains for 2 hours and 30 minutes three times perweek. How many minutes per week does the team train?2. An octave of music includes 8 notes. If you were to go up half anoctave, how many notes is that?3. You walk a distance of 2 km north, 3 km east, and then 2.5 km to thenorthwest. What total distance did you walk?Answers45047.5 km4. Write the percent as a decimal: 62%0.625. You buy some popcorn for 3.80. You give the cashier a 5 bill. Howmuch change do you receive? 1.20Unit Questions3to a percent.475%1in percent form.812.5%6. Convert7. Write8. Your salary is 10 dollars per hour. You get a raise of 0.40 dollars perhour. What is the salary increase as a percent?Other Questions9.10.4%

Mental MathGrade 10 Essential Mathematics (20S)Unit A: Gross Pay, Time Cards, and PercentsGeneral QuestionsA–4Answers1. You are going to the store to buy a drink with 2.05 in your pocket.If a drink costs 1.75, will you be able to buy one?Yes2. Which is larger, 0.76 or 0.07?0.763. Solve for g: 3 - g 15-124. Is an angle with a measurement of 86 acute, right, obtuse, straight, orreflex?acute5. Complete the pattern: 4, 1, -2,,-5, -8Unit Questions6. Bernard works 30 hours at a rate of 25 dollars per hour. What is hisgross pay? 7507. Marcel’s annual salary is 72,000. What is his monthly salary? 60008. Erika earns a salary of 1500 per week. What is her annual salary?Other Questions9.10. 78,000

Mental MathGrade 10 Essential Mathematics (20S)A–5Unit A: Gross Pay, Time Cards, and PercentsGeneral QuestionsAnswers1. You take swimming lessons 4 days out of 5. What percent does thisrepresent?80%2. A basic calculator has 6 rows and 5 columns of buttons. How manybuttons does it have in total?303. Three students receive their marks for a project. Jane found her markas a decimal, 0.62; John calculated his mark as a percent, 73%; Jean got12. Who got the best mark?164. What value is larger, 80% or5. If 0.333 15?201, then what does 0.666 equal?3Jean80%23Unit Questions6. What value represents 1% of 400,000? 40007. You receive a commission of 20% for all your sales. You sell 15,000 ofgoods. What amount of commission will you receive? 30008. Carole sells 2400 worth of hats. If each hat costs 40, how many hatsdid Carole sell?60Other Questions9.10.

Mental MathGrade 10 Essential Mathematics (20S)Unit A: Gross Pay, Time Cards, and PercentsGeneral QuestionsAnswers1. Candy regularly costs 40. What is the cost after a discount of 40%?2. Rewrite the following fraction in lowest terms:A–618273. There is a 50% discount on all candy at the store the day afterHallowe’en. If it cost you 30 to buy candy before Hallowe’en,how much would you spend if you bought the same candy afterHallowe’en? 2423 154. What is the mean of 3, 4, 6, and 7?55. Jamie is twice as old as Dan. Dan is 3 times as old as Kim. If Kim is4 years old, how old is Jamie?24Unit Questions6. You worked 7 hours each day of the week except Sunday. How manyhours did you work in the week?427. A normal workweek is 40 hours. If you work 52 hours, how manyhours of overtime did you work?128. How many more hours must you add to 5.25 hours to have a total of8 hours?Other Questions9.10.2.75

Mental MathGrade 10 Essential Mathematics (20S)A–7Unit A: Gross Pay, Time Cards, and PercentsGeneral QuestionsAnswers1. There are 60 candies in a box. If you eat one candy each day, how manycandies are there in the box after 8 full weeks?2. Complete the following pattern: 60, 75,, 105,3. Is an angle of 235 an acute, an obtuse, a right, a straight, or a reflexangle?4. Evaluate: 4 - 6 2 (3 - 8).5. There are 3 pairs of socks in a package. If the whole package costs 6,how much does it cost per pair of socks?490, 120reflex-12 2Unit Questions6. Evaluate: 10.75 27.507. How many hours are there between 9:00 a.m. and 5:00 p.m.?8. You leave the house at 7:30 a.m. You return to the house at 3:45 p.m.How many minutes are you gone from the house?Other Questions9.10.38.258495

Mental MathGrade 10 Essential Mathematics (20S)Unit A: Gross Pay, Time Cards, and PercentsGeneral QuestionsA–8Answers1. What is 10% of 500?502. What is 5% of 500?253. What is 15% of 500?754. Paul lives 2 km to the south of your house. Pierre lives 4 km to thenorth of your house. What is the distance between the houses of Pauland Pierre?6 km5. You give the cashier a 10 bill to pay for your lunch. If the total for yourlunch is 7.60, how much change will you get back? 2.40Unit Questions6. Jack and John are paid by commission. Jack receives 9% of 5000 ofsales. John receives 8% of 6000 of sales. Who receives more and byhow much?7. Marc earns 20; Jean earns twice as much as Marc; Lionel earns twiceas much as Jean. How much do Marc, Jean, and Lionel earn in total?8. Tom earns a weekly base salary of 500. If Tom works 48 weeks peryear, what is Tom’s annual base salary?Other Questions9.10.John; 30 140 24,000

Mental MathGrade 10 Essential Mathematics (20S)Unit B: Net PayGeneral QuestionsB–1Answers1. It costs 4.00 for a package of 3 chocolate bars. Geri spends 20 onchocolate bars. How many chocolate bars does she buy?152. You worked 35 hours this week. Your hourly wage is 10. How muchwas your gross pay? 3503. You walk 8 km north, 6 km east, 3 km north, and finally 4 km west.What distance have you walked?21 km4. Write the percent as a decimal: 3.5%.0.0355. Arrange the numbers from largest to smallest:13, 0.29 , , 0.65 , 0.342431, 0.65 , , 0.34 , 0.2942Unit Questions6. Deductions of 16.85 for CPP and 10.55 for EI are made to your salary.What is the total deduction? 27.407. How much income tax do you pay on each cheque if the provincial taxis 42 and the federal tax is 56 each time? 988. True or False? Net pay is more than gross pay.Other Questions9.10.False

Mental MathGrade 10 Essential Mathematics (20S)Unit B: Net PayGeneral Questions1. What are the factors of 8?B–2Answers1, 2, 4, 82. You are getting ready for a barbeque you are hosting. It costs 1.50 for apackage of 30 plastic cups. How much does each plastic cup cost? 0.053. You buy 2 packs of hotdogs at 12.00 each and 3 packs of chickenburgers at 15.00 each. How much must you pay in total? 69.004. Write the following decimal as a fraction: 0.0585. Solve for h: h 12 325829or100050020Unit Questions6. You pay 33.01 for CPP for your gross salary of 734.07. What is yoursalary after this deduction? 701.067. Marie’s gross salary is 576.49. After a deduction for CPP, her pay is 552.49. How much is the CPP deduction? 24.008. After a deduction for CPP of 26.02, Linda’s net pay is 653.46. What isLinda’s gross pay? 679.48Other Questions9.10.

Mental MathGrade 10 Essential Mathematics (20S)Unit B: Net PayGeneral QuestionsAnswers1. You were paid 180 from your part-time job. Your hourly wage is 9.How many hours did you work?2. Which is smaller:B–347or?5107103. Add: 3 6 7 4 3234. You want to save 12,000 to buy a car 1 year from now. How much doyou have to save per month to reach this goal?5. Rewrite the fraction in lowest terms:203321 1000117Unit Questions6. If you pay 5% to CPP and your monthly income is 5000, how much isyour CPP deduction each month? 2507. Your monthly income is 400. You owe 4.95% of your income for CPP.Do you owe more than or less than 20 for CPP?less8. If you pay 30 in CPP for a week, how much do you owe per year?Other Questions9.10. 1560

Mental MathGrade 10 Essential Mathematics (20S)B–4Unit B: Net PayGeneral Questions1. What is 4 timesAnswers1?222. There are approximately 2.5 cm in 1 inch. A table measures 50 incheslong. What is the approximate length of the table in centimetres?1253. You are out for dinner with your best friend for his birthday. The billcomes and you pay for everything. If the total is 35.75 and you leave 40 on the table (including tip), how much are you tipping the server? 4.254. Is an angle that measures 35 acute, right, obtuse, straight, or reflex?acute5. Estimate the CPP (4.95%) if the gross pay is 600. 30Unit Questions6. You owe 10.20 in EI for a gross salary of 589.89. What is your salaryafter this deduction? 579.697. Marie’s gross salary is 636.00. Her net salary is 625.00 after deductingEI. How much does she owe for EI? 11.008. After a CPP deduction of 9.50, Linda’s net salary is 540.00. What isher gross pay? 549.50Other Questions9.10.

Mental MathGrade 10 Essential Mathematics (20S)B–5Unit B: Net PayGeneral QuestionsAnswers1. What is the range of the following numbers: 0.2, 0.6, 0.08, 0.5, 0.03?0.572. A dozen muffins costs 8.66. How much would you expect half a dozenmuffins to cost? 4.333. Solve for d: 3d 934. Subtract: 46 - 29175. If 2 blocks on a street have a length of 100 m, how many metres long is5 blocks?250Unit Questions6. If you owe 1.5% for EI and your monthly income is 1000, how much doyou owe for EI? 15.007. Your monthly income is 400. You owe 1.73% of your income for EI.Do you owe more or less than 7 for EI?less8. If you owe 11 for CPP each week, how much do you owe in one year? 572Other Questions9.10.

Mental MathGrade 10 Essential Mathematics (20S)Unit B: Net PayGeneral Questions1. Estimate the EI (1.5%) charged if you have a gross pay of 250.2. List four different methods of payment for work.B–6Answers 4piecework,commission,annual salary,hourly rate3. You buy a waffle iron for your mother for her birthday. The waffle ironcosts 40 (taxes included) a

Contentsiii C o n t e n t s Introduction 1 Why Mental Mathematics 3 Strategies 4 Document Features 4 Methodology 5 Assessment 6 Reproducible Sheets 1 Examples of Strategies 1 Mental Math Questions by Unit 1 Unit A: Gross Pay, Time Cards, and Percents Unit B: Net Pay Unit C: Measurement Unit D: Geometry Unit E: Angles and Parallel and Perpendicular Lines Unit F: Consumer Decisions