# w.c. 4.10.2021

Monday - subtract two 4-digit numbers with one exchange

## Monday - Subtract two 4-digit numbers (one exchange)

We have carried this lesson over from the previous week.  Please continue to practise subtractions using one exchange or have a look at the next lesson if you are ready to move on.

Tuesday - subtract two 4-digit numbers with more than one exchange

## Tuesday - Subtract two 4-digit numbers (more than one exchange)

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Can you solve these calculations?

9231 - 7114 =

5830 - 1752 =

3001 - 1627 =

You might like to try the investigation below:

Wednesday - subtract numbers with more than 4 digits

## Wednesday - Subtract whole numbers with more than 4 digits

Remembering to line up the digits in the correct columns, can you solve the following subtractions?

37684 - 893 =

4275 - 1937 =

Find the difference between 57823 and 8465

Katie does 11,273 steps but Joe only manages 9176.  How many more steps does Katie do than Joe?

See below for some problem solving activities

Thursday - rounding to estimate and approximate

## Thursday - Round to estimate and approximate

We can use rounding and approximating to help us get more of an idea of whether our calculations are correct or not.  It is a useful tool!

For some of your calculations from the previous days, can you round your numbers to the nearest 1000 or 100 (as appropriate) then subtract them to see whether your answer was approximately the right size?

Try it for these additions too:

4367 + 8729 =

29371 + 459 =

6710 - 197 =

Friday - use the inverse operation

## Friday - Inverse operations (addition and subtraction)

We can use the inverse operation to check our calculations.

Use a dice or choose some numbers to create an addition involving two 4-digit numbers.  Carry out the addition then do the related subtraction to check that your working is correct.

Repeat for a subtraction, using the related addition to check your working.

Try the problem solving below for some extra challenges.

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