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Reasoning and Problem SolvingSpring - Block 2Percentages

Year 6 Spring Term Week 3 to 4 – Number: PercentagesOverviewSmall StepsNotes for 2020/21Children should have beenintroduced to percentages brieflyin Y5 but this work may havebeen missed. Time spentexploring 100 as a denominator,making the link to decimals andhundredths is important.Bar models and hundred squaresshould be used to supportunderstanding.Understand percentagesFractions to percentagesEquivalent FDPOrder FDPPercentage of an amount (1)Percentage of an amount (2)Percentages – missing values2

Year 5 Spring Term Week 10 to 11 – Number: Decimals & PercentagesUnderstand PercentagesVaried FluencyNotes and GuidanceComplete the sentence stem for each diagram.Children are introduced to ‘per cent’ for the first time and willunderstand that ‘per cent’ relates to ‘number of parts perhundred’.They will explore this through different representations whichshow different parts of a hundred. Children will use ‘numberof parts per hundred’ alongside the % symbol.There are parts per hundred shaded. This is %Complete the table.Mathematical TalkHow many parts is the square split in to?How many parts per hundred are shaded/not shaded?Can we represent this percentage differently?Complete the bar models.Look at the bar model, how many parts is it split into?If the bar is worth 100%, what is each part worth?3 White Rose Maths

Year 5 Spring Term Week 10 to 11 – Number: Decimals & PercentagesUnderstand PercentagesReasoning and Problem SolvingOh no! Dexter has spilt ink on hishundred square.Mo, Annie and Tommy all did a test with100 questions. Tommy got 6 fewerquestions correct than Mo.Some possibleanswers:It could be 25%It must be lessthan 70%56%65 out of 10050 out of 10050%It can’t be 100%Complete the sentence stems todescribe what percentage is shaded.Complete the table.How many more marks did each childneed to score 100%?Mo needs 44Annie needs 35Tommy needs 50It could be Dora and Amir each have 100 sweets.Dora eats 65% of hers. Amir has 35sweets left.Who has more sweets left?It must be It can’t be 4Neither. They bothhave an equalnumber of sweetsremaining. White Rose Maths

Year 6 Spring Term Week 3 to 4 – Number: PercentagesFractions to PercentagesVaried FluencyNotes and GuidanceWhat fraction of eachhundred square is shaded?Write the fractions aspercentages.It is important that children understand that ‘percent’ means‘out of 100’.Children will be familiar with converting some commonfractions from their work in Year 5They learn to convert fractions to equivalent fractions wherethe denominator is 100 in order to find the percentageequivalent.Complete the table.Mathematical TalkWhat does the word ‘percent’ mean?Fill in the missing numbers.1235 1% 35%100100How can you convert tenths to hundredths?Why is it easy to convert fiftieths to hundredths?What other fractions are easy to convert to percentages?12 250 10054%4422 22%200 100

Year 6 Spring Term Week 3 to 4 – Number: PercentagesFractions to PercentagesReasoning and Problem SolvingIn a Maths test, Tommy answered 62%of the questions correctly.3Rosie answered of the questions5correctly.Tommy answeredmore questionscorrectly because3as a percentage5is 60% and this isless than 62%Dora is correctbecauseWho answered more questions correctly?Amir thinks that 18% of the grid has beenshaded.Explain your answer.Dora thinks that 36% of the grid has beenshaded.Who do you agree with?Explain your reasoning.61850 36100

Year 6 Spring Term Week 3 to 4 – Number: PercentagesEquivalent FDPVaried FluencyNotes and GuidanceComplete the table.Children use their knowledge of common equivalent fractionsand decimals to find the equivalent percentage.A common misconception is that 0.1 is equivalent to 1%.Diagrams may be useful to support understanding thedifference between tenths and hundredths and their equivalentpercentages.Use , or to complete the statements.Mathematical TalkHow does converting a decimal to a fraction help us to convertit to a percentage?How do you convert a percentage to a decimal?0.3640%0.425%70.071010.44Which of these are equivalent to 60%?Can you use a hundred square to represent your conversions?60100761000.06353500.6

Year 6 Spring Term Week 3 to 4 – Number: PercentagesEquivalent FDPReasoning and Problem SolvingAmir says 0.3 is less than 12% because 3is less than 12Amir is wrongbecause 0.3 isequivalent to 30%How many different fractions can youmake using the digit cards?1 2 3 4 5 6Explain why Amir is wrong.Complete the part-whole model.How many different ways can youcomplete it?B 0.2, 20%,1How many of the fractions can youconvert into decimals and percentages?3A 0.3, 30% or10210Children make arange of fractions.They should beable to convert1 1 2 3 1 2 3, , , , , ,2 4 4 4 5 5 54and into5decimals andpercentages.or5C 0.1, 10% orPossible answers:110Can you create your own version withdifferent values?8

Year 6 Spring Term Week 3 to 4 – Number: PercentagesOrder FDPVaried FluencyNotes and GuidanceUse , or to complete the statements:Children convert between fractions, decimals and percentagesto enable them to order and compare them.Encourage them to convert each number to the same form sothat they can be more easily ordered and compared. Once thechildren have compared the numbers, they will need to putthem back into the original form to answer the question.0.630.2324%137.6%38540.27Order from smallest to largest:Mathematical Talk40%50%What do you notice about the fractions, decimals orpercentages? Can you compare any straight away?250.4531054%0.05Four friends share a pizza. Whitney eats 35% of the pizza, Teddyeats 0.4 of the pizza, Dora eats 12.5% of the pizza and Alex eats0.125 of the pizza.What is the most efficient way to order them?Do you prefer to convert your numbers to decimals, fractionsor percentages? Why?If you put them in ascending order, what will it look like?If you put them in descending order, what will it look like?60%Write the amount each child eats as a fraction.Who eats the most? Who eats the least? Is there any left?9

Year 6 Spring Term Week 3 to 4 – Number: PercentagesOrder FDPReasoning and Problem SolvingIn his first Geography test, Mo scored38%16In the next test he scored40Did Mo improve his score?Explain your answer.Mo improved hisscore.16is equivalent toWhich month did Eva save the mostmoney?Estimate your answer using yourknowledge of fractions, decimals andpercentages.Explain why you have chosen that month.4040% which isgreater than hisprevious score of38%3In January, Eva saves of5her 20 pocket money.In February, she saves 0.4of her 10 pocket money.In March, she saves 45% ofher 40 pocket money.10She saved themost money inMarch.Estimates:Over 10 inJanuary because35is more than half.Under 10 inFebruary becauseshe only had 10to start with and0.4 is less thanhalf.Nearly 20 inMarch because45% is close to ahalf.

Year 6 Spring Term Week 3 to 4 – Number: PercentagesPercentage of an Amount (1)Varied FluencyNotes and GuidanceEva says,Children use known fractional equivalences to findpercentages of amounts.Bar models and other visual representations may be useful in1supporting this e.g. 25% so we divide into 4 equal parts.4In this step, we focus on 50%, 25%, 10% and 1% only.150% is equivalent to2To find 50% of an amount, I can divide by 2Complete the sentences.125% is equivalent toTo find 25% of an amount, divide by10% is equivalent to1% is equivalent toMathematical Talk11To find 10% of an amount, divide byTo find 1% of an amount, divide byUse the bar models to help you complete the calculations.Why do we divide a quantity by 2 in order to find 50%?How do you calculate 10% of a number mentally?50% of 406 What’s the same and what’s different about 10% of 300 and10% of 30?11Find:50% of 300 25% of 30050% of 30 25% of 3050% of 60 25% of 6025% of 124 10% of 30010% of 3010% of 601% of 3001% of 301% of 60

Year 6 Spring Term Week 3 to 4 – Number: PercentagesPercentage of an Amount (1)Reasoning and Problem SolvingMo says,To find 10% you divide by10, so to find 50% youdivide by 50Do you agree? Explain why.Eva says to find 1% of a number, youdivide by 100Whitney says to find 1% of a number, youdivide by 10 and then by 10 again.Possible answer:Complete the missing numbers.Mo is wrongbecause 50% isequivalent to a halfso to find 50% youdivide by 250% of 40 % of 80% of 40 1% of 40010% of 500 % of 100They are bothcorrect.Whitney hasdivided by 100 intwo smaller steps.Who do you agree with?Explain your answer.12251050

Year 6 Spring Term Week 3 to 4 – Number: PercentagesPercentage of an Amount (2)Varied FluencyNotes and GuidanceMo uses a bar model to find 30% of 220Children build on the last step by finding multiples of 10% andother known percentages.They explore different methods of finding certain percentagese.g. Finding 20% by dividing by 10 and multiplying by 2 or bydividing by 5. They also explore finding 5% by finding half of10%. Using these methods, children build up to findpercentages such as 35%.10% of 220 22 , so 30% of 220 3 22 66Use Mo’s method to calculate:Mathematical Talk40% of 220 20% of 11030% of 440 90% of 460Is dividing by 10 and multiplying by 5 the most efficient way tofind 50%? Explain why.To find 5% of a number, divide by 10 and then divide by 2Use this method to work out:(a) 5% of 140(b) 5% of 260(c) 5% of 1 m 80 cmIs dividing by 10 and multiplying by 9 the most efficient way tofind 90%? Explain why.How else could we work out 5%?Calculate:How many ways can you think of to calculate 60% of anumber?15% of 60 m1335% of 300 g65% of 20

Year 6 Spring Term Week 3 to 4 – Number: PercentagesPercentage of an Amount (2)Reasoning and Problem SolvingFour children in a class were asked tofind 20% of an amount, this is what theydid:I divided by 5 because20% is the same as onefifthWhitneyI found one percent bydividing by 100, then Imultiplied my answer by 20AmirI did 10% add 10%AlexI found ten percent bydividing by 10, then Imultiplied my answer by 2All methods areacceptable waysof finding 20%Children may havedifferent answersbecause they mayfind differentmethods easier.Discussion couldbe had aroundwhether or nottheir preferredmethod is alwaysthe most efficient.How many ways can you find 45% of 60?Use similar strategies to find 60% of 45Possible methodsinclude:10% 4 5%What do you notice?25% 20%Does this always happen?Can you find more examples?25% 10% 10%50% 5%To find 60% of 4510% 650% 10%10% 3Children willnotice that 45% of60 60% of 45JackWho do you think has the most efficientmethod? Explain why.Who do you think will end up getting theanswer incorrect?This alwayshappens.14

Year 6 Spring Term Week 3 to 4 – Number: PercentagesPercentages – Missing ValuesVaried FluencyNotes and GuidanceChildren use their understanding of percentages to find themissing whole or a missing percentage when the other valuesare given. They may find it useful to draw a bar model to helpthem see the relationship between the given percentage oramount and the whole.350,000 people visited the Natural History Museum last week.15% of the people visited on Monday.40% of the people visited on Saturday.How many people visited the Natural History Museum during therest of the week?It is important that children see that there may be more thanone way to solve a problem and that some methods are moreefficient than others.If 7 is 10% of a number, what is the number?Use the bar modelto help you.Mathematical TalkIf we know a percentage, can we work out the whole?Complete:If we know the whole and the amount, can we find whatpercentage has been calculated?10% of 150 1530% of 150 4530% of 300 9030% of 300 900What diagrams could help you visualise this problem?Is there more than one way to solve the problem?Can you see a link between the questions?What is the most efficient way to find a missing value?15

Year 6 Spring Term Week 3 to 4 – Number: PercentagesPercentages – Missing ValuesReasoning and Problem SolvingWhat percentage questions can you askabout this bar model?Fill in the missing values to make thisstatement correct.Can you find more than one way?Possible answer:If 20% of anumber is 3.5,what is the whole?What is 60%?What is 10%?A golf club has 200 members.58% of the members are male.50% of the female members are children.(a) How many male members are in thegolf club?(b) How many female children are in thegolf club?.Possible answers:25% of 60 25% of 6025% of 120 50% of 6025% of % of 6025% of 24 10% of 6025% of 2.4 1% of 6025% of 180 75% of 6016116 malemembers42 female children

Children build on the last step by finding multiples of 10% and other known percentages. They explore different methods of finding certain percentages e.g. Finding 20%by dividing by 10 and multiplying by 2 or by dividing by 5. They also explore finding 5% by finding half of 10%. Using these m

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