How_To_Be_Good_At_Math

CALCULATING • MORE LONG MULTIPLICATION 123

Next, multiply 7 thousands by 3 ones.

The answer is 21 thousands. Write 1

in the thousands column and 2 in the ten

thousands column.

7242 × 23 = 166 566

ThTThHTh H T O

7242

23

21726

×

Multiply

7 thousands

by 3 ones

Now we’re going to multiply all the

digits on the top row by 2 tens and

write the answers on a new line. When

we multiply by the 2 tens, we’re actually

multiplying by 20, which is 10 times 2.

So, first we put a 0 in the ones column

on the new line as a place holder.

Next, we multiply each of the digits in

the top row by the 2 tens, in the same

way that we did when we multiplied the

top row by 3. The answer on the bottom

line is 144 840.

ThTThHTh H T O

7242

23

21726

×

This 2 means

2 tens, or 20

Put a 0 on a

new line in the

ones column

Now we have multiplied all the digits

on the top row by all the digits on the

bottom row, we use column addition to

add the two lines in our answer together:

21 726 + 144 840 = 166 566

ThTThHTh H T O

7242

×^23

Multiply each

digit on the

top row by

21726 2 tens

144840

So, 7242 × 23 = 166 566

0

1

1

1

ThTThHTh H T O

7242

×^23

Add the

two answers

together

21726

144840

166566

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122-123_More_long_multiplication.indd 123 29/02/2016 14:11