How_To_Be_Good_At_Math

CALCULATING • EXPANDED COLUMN SUBTRACTION 95

H T

Now we just need to add the

24 that will take the total from

300 to 324. Write the 2 in the tens

column and the 4 in the ones column.

Finally, we need to find the total of

all the numbers that we added on:

2 + 20 + 100 + 24 = 146

So, 324 – 178 = 146

Now, we add hundreds. Adding

100 takes us from 200 up to 300.

Write the 1 in the hundreds column and

the zeros in the tens and ones columns.

Write the new total on the right.

324

1 78

H T O

2

Adding 100 to

200 takes the

total up to 300

20

100

324

1 78

H T O

2 180

Adding 24 to

300 takes the

total up to 324

20200

100300

180

200

300

Answers on page 319

Find the difference

Can you use expanded

column subtraction to find

the difference between

these numbers?

TRY IT OUT

−

−

24324

−

324

1 78

O

180

Find the total of

the numbers

we've added on

200

300

324

2

20

100

24

146

9425 − 5832 =?

817 − 394 =?

283 − 76 =?

We arrived at our answer

by adding ones, tens,

and hundreds in steps,

like shopkeeper’s

addition (page 93).

324 − 178 = 146

094_095_Expanded_column_subtraction.indd 95 29/02/2016 14:10