[PDF] To add and subtract decimals within 1 - Blessed Dominic

2586_6Decimals_PDF_2.pdf

27/4/2020 LO: To add and subtract decimals within 1.Success Criteria: - I can add and subtract decimals within one whole efficiently. - I can use a place value chart to support my understanding of when we exchange between columns. - I can build on my understanding that 0.45 is 45 hundredths and can use a hundred square to add and subtract decimals.

Today you will need your place value ruler that was included in your home learning pack. You can also sketch out your own place value chart on a piece of scrap paper. Today you will be focusing on ones, tenths and hundredths, so draw your place value chart like the one below: OnesTenthsHundredthsDon't forget your decimal point!

Videos to support today's learning:White Rose Maths: Summer Term - Week 1 Lesson 1 - Adding decimals within 1 Lesson 2 - Subtracting decimals within 1 https://whiterosemaths.com/homelearning/year-5/ Youtube Mossford Green - Adding decimals within 1 https://www.youtube.com/watch?v=JbGdrXW1z7U Youtube Mossford Green - Subtracting decimals within 1 https://www.youtube.com/watch?v=3m2y-QZgHS0

When adding and subtracting decimals, it is important to understand the place value of the numbers. You will need to use your place value grid.

We already know that 0 is a place holder. Today when adding and subtracting decimals we might want to use zeros so that the numbers are the same length. A zero is really saying "there is no value at this decimal place". In a number like 10, the zero is saying "no ones" In a number like 2.50 the zero is saying "no hundredths' It is safe to take a number like 2.5 and make it 2.50 or 2.500 etc. because adding zeros does not effect the value of the number. But you cannot take 2.5 and make it 20.5 as adding a zero in-between integers changes the number completely. E.g. If we are adding 2.5 + 2.22 we might want to put in zeros to make then numbers the same length. For example:OTthHth020072092+=

We can use a number line and bar model to add decimals. For example, 0.3 + 0.50.30.5We can now combine our bar models:0.30.5So we can now see 0.3 + 0.5 = 0.8

We can use a part whole model to add decimals. For example, 0.6 + 0.30.60.30.9 = 9 tenths 6 tenths3 tenths

We can also use a hundred square to add decimals. In this hundred square, each box represents one hundredth of the whole.0.78 + 0.07So now we can see 0.78 + 0.07 = 0.85

Adding decimals using a place value grid:OnesTenthsHundredthsThousandths07320.10.10.10.10.10.10.10.010.010.010.0010.001+=

This time we need to exchange because there are eleven hundredthsOnesTenthsHundredthsThousandths0.10.10.10.10.10.010.010.001+=0.0010.0010.0010.010.010.010.010.010.010.010.010.01We can exchange 10 hundredths for one tenth

OnesTenthsHundredthsThousandths06140.10.10.10.10.10.001+=0.0010.0010.0010.010.1

Adding decimals using the column method (you can continue to label the place value when using column method to help you):OnesTenthsHundredthsThousandths040203200722+=First, you need to line up your decimals, remembering that the decimal point needs to stay in the same place.You can place a zero here if you want to make the decimal numbers the same length.

We can use a number line and bar model to subtract decimals. For example, 0.8 - 0.40.80.4We can now combine our bar models:So we can now see 0.8 - 0.4 = 0.4

We can also use a part whole model to subtract decimals. For example, 0.06 - 0.050.050.01 = 1 hundredth5 hundredths0.066 hundredthsSo, 0.06 - 0.05 = 0.01

Subtracting decimals using a place value grid:OnesTenthsHundredthsThousandths02230.10.10.10.10.010.010.010.0010.0010.010.010.10.10.0010.0010.654 - 0.431

This time we need to exchange 0.61 - 0.35OnesTenthsHundredths0.10.10.10.10.1=0.01We need to exchange one tenth for ten hundredths0.1OTthHth061035-

This time we need to exchange 0.61 - 0.35OnesTenthsHundredths0260.10.10.10.1=0.010.1OTthHth061035026-0.010.010.010.010.010.010.010.010.010.0115

Your TaskView your task on the class page Challenge 1: Complete parts 1 - 3 Challenge 2: Complete parts 1 - 4 Challenge 3: Complete parts 1 - 5 Try the mastery challenge!