How_To_Be_Good_At_Math

CALCULATING • EXPANDED LONG MULTIPLICATION 119

First, multiply 7 ones by 1 ten.

The answer is 7 tens, or 70.

On another new line, write 7 in the

tens column and 0 in the ones column.

So, 37 × 16 = 592

Now we’re going to multiply all the

digits on the top row by 1 ten and

continue to write the answers below.

37 × 16 = 592

Next, multiply 3 tens by 1 ten.

The answer is 30 tens, or 300, because

we are multiplying 30 by 10. On a new line,

write 3 in the hundreds column, 0 in the

tens column, and 0 in the ones column.

Now we have multiplied all the digits

on the top line by all the digits on the

second line, we add all four lines in our

answer together:

42 + 180 + 70 + 300 = 592

We’re going to

multiply each

digit in the top

row by 1 ten

×

42

180

H T O

37

16

37

16

Multiply 7 ones

by 1 ten

H T O

×

42

180

70

37

16

Multiply 3 tens

by 1 ten

H T O

×

42

180

70

300

37

16

42

Add the four

answers together

×

180

300

592

1 When we add

4 tens, 8 tens,

7 tens, and

0 tens, we get

19 tens, so carry

the 1 into the

hundreds column

H T O

70

118_119_Expanded_long_multiplication.indd 119 29/02/2016 14:11