How_To_Be_Good_At_Math

144 CALCULATING •^ EXPANDED LONG DIVISION

Expanded long division

When the number we are dividing by (the divisor) has more than one digit, we use

a method of calculation called long division. Here, we look at expanded long

division. There’s also a shorter version just called long division (see pages 146-47).

To see what expanded long division

is like, we’ll divide 4728 by 34.

Before we begin dividing, we write

down the number we want to

divide, the dividend, which is 4728.

Then we draw a division bracket

around it. We put the divisor, 34,

outside the bracket, to the left of 4728.

Now we’re all set to start dividing.

Just as we did with expanded short

division, we’ll take away big chunks of the

number each time. The easiest big chunk

to take away is 100 groups of 34, which is

3400. When we subtract 3400 from 4728,
      we’re left with 1328. We write the number
      of 34s on the right.

We can’t subtract another 3400

from 1328, so we’ll need to use a

smaller chunk. Fifty groups of 34 would

be 1700. Forty groups would be 1360.

Both numbers are too large. What

about 30 groups of 34? That gives us

1020. Let’s subtract 1020 from 1328,
      which leaves us with 308.

4728 ÷ 34 =?

You may find it

useful to label

the columns to

show place values

Draw a line and write

what’s left over here,

keeping digits with

the same place values

lined up

1328 − 1020 = 308

(34 × 100)

(34 × 100)

−

−

34

34

34

H

H

H

− (34 × 30)

We write down

how many 34s

we subtracted

Record another

30 groups of 34

T

T

T

O

O

Th O

7

7

7

4

4

4

2

2

2

8

8

8

4

4

3

3

0

0

0

0

3

3

1

1

2

2

8

8

(^1020)
3 0 8
Th
Th
144-145_Expanded_long_division.indd 144 29/02/2016 18:56