Adding Decimals

Adding DecimalsL.O: to use column addition to add decimal numbersSteps to SuccessRead the questionWrite the numbers. Estimate an answerWrite the numbers, lining up the decimal points.Fill in any spaces in the columns with 0 then add the two decimal numbers.Is your answer close to your estimate if not go back and re-do the sum.Compact Column AdditionWhen we want to add two numbers we can use the compact methodE.g 57 + 29 1 T U 5 7 2 9+ 8 6On Whiteboards58 + 27 =89 + 56 =123 + 567What is this

5.6This is a decimal number 5.6

Whole number part of a number (1/10)Adding DecimalsWhen we add decimals we use the compact method e.g 2.3 + 3.4 u.1/102.3 3.4 + 5.7 We must make sure the decimal numbers are lined up correctly the decimal points must always be underneath each other Adding decimalsAdd 3.7 and 4.1 u.1/10 3.7 4.1 + 7.8 Again we must make sure that the decimal points are underneath each other. On Whiteboards2.4 + 2.4 =3.2 + 4.2 =5.1 + 3.5 =4.5 + 6.2 =7.4 + 3.3 =Adding Decimals2.5 + 2.6 1 U . 1/10 2 . 5 2 . 6 5 . 10.5 + 0.6 = 1.1 not 0.11Adding decimals 4.6 + 3.8 1 u. 1/10 4. 6 3. 8 8. 4Remember 0.6 + 0.8 = 1.4 not 0.14

On Whiteboards Try this one

2.9 + 4.7

U.1/10 2.9 4.7On Whiteboards5.5 + 6.73.9 + 8.56.9 + 4.812.5 + 3.9

PlenaryHow would you solve9 + 3.812 + 4.913Milan, Hrishikesh and Jaimin worked with KP Maimoona and Veeshali worked with UMAdding Decimals Day 2Re-cap add the following decimal numbers2.1 + 3.4 4.3 + 2.2 +3.15 + 4.8

Adding DecimalsIn yesterdays work we were adding decimals which had the same number of numbers after the decimal point

2.5 + 3.6

One number after the decimal point One number after the decimal pointAdding DecimalsWhat do we do when we have un-equalnumbers after the decimal point?e.g 2.34 + 3.2

To make the numbers the same we add a zero to the 3.2.So we can re-write the sum as

2.34 + 3.20

Two numbers after the decimal point two numbers after the decimal point

Adding DecimalsTry this one

2.12 + 5.6 check to see if the numbers are equal if not add on a zeroRe- write as 2.12 + 5.60 u . 1/10 1/100 2 . 1 2 5 . 6 0 7 . 7 2Now we can add as normal

2.34 + 3.20 = u.1/10 1/100 2. 3 4 3. 2 0 + 5. 5 4On Whiteboards2.7 + 3.56

6.78 + 2.2

12.43 + 3.36

23.45 + 11.7

PlenaryCalculate 52.85 + 143.620Jaimin Hrishikesh and Milan worked with BD Maimoona and Veeshali with UM

Milan Jaimin Hrishikesh with BD Veeshali and Maimoona with UM children from 5NWF to CLC 11.40 Decimal Addition Word ProblemsL.O: to solve decimal addition word problems.Re-capOn whiteboards3.4 + 6.9 =12.3 + 9 =23.51 + 2.8=Steps to SuccessRead the question circle the numbers in the question.Write the numbers. Estimate an answerWrite the numbers, lining up the decimal points.Fill in any spaces in the columns with 0 then add the two decimal numbers.Is your answer close to your estimate if not go back and re-do the sum.Use a calculator to check your answer.

On WhiteboardsQuickly write down other words for Word ProblemsAsh travels 3.8km to school, Mina travels 4.9km to school. How far do they travel altogether?To answer this question underline/circle all the important information.What have you underlined?Ash travels 3.8km to school, Mina travels 4.9km to school. How far do they travel altogether?

The numbers and the operation is what you should have underlined.Altogether means + so we have to add the two numbersEstimate first Round the decimals to the nearest whole number3.8 = 4 4.9 = 5 So our answer should be close to 4 + 5 = 9 kmNow add the two numbers, remember to line up the decimals correctly

1 3.8 4.9 + 8.7So our answer is 8.7 km which is close to our estimate of 9 km

Another ProblemKiran has three bags of sweets one weighs 4.17g, one weighs 8.2g and the third weighs 6.47g. What is the total weight of the sweets?

Underline/circle all the important information.

Kiran has three bags of sweets One weighs 4.17g, one weighs 8.2g and the third weighs 6.47g. What is the total weight of the sweets?

Total = +4.17g + 8.2g +6.47g

Estimate first4.17g + 8.2g +6.47gRound each decimal to the nearest whole number4.17 = 48.2 = 86.47 = 64 + 8 + 6 = 18 So our answer should be close to 18

Line up the decimals 4. 1 7 8. 2 6. 4 7Fill up any blank spaces with 0 1 4. 1 7 8. 2 0 6. 4 7 + 18. 84

Which is close to our estimate of 18 On WhiteboardsAjay runs 7.14km on Monday, 6.5km on Tuesday and 19.46km on Wednesday. What is the total distance that he runs on the three days.Write the important information on your whiteboard.Solve this word problemRemember to estimate first!Ajay runs 7.14km on Monday, 6.5km on Tuesday and 19.46km on Wednesday. What is the total distance that he runs on the three days.Total = +7.14 = 76.5 = 719.46 = 19Estimate = 7+7+19=33

7.14 6.5019.4633.10

PlenaryA man has three parcels.Parcel 1 weighs 24.8 kgParcel 2 - weighs double parcel 1Parcel 3 - weighs half of parcel 1 What is the total weight of the three parcels?