 # Long Multiplication

 From: Hannah Simson Date: 9 July 2000 Subject: How to do long multiplication Please explain how to do long multiplication.

### Maths Help suggests:

Long multiplication is a way to multiply numbers with 2 or more digits.

Here is an example of a long multiplication of two 2-digit numbers:

37 × 28

First, set out the two numbers in columns like this:

 3 7 × 2 8

Then (being careful with the columns) work out 8 times 37:

8 × 7 = 56:

 3 7 × 2 8 6 5
then

8 × 3 = 24:

 3 7 × 2 8 2 9 6 5

Place a zero in the right-most column on the next row,

 3 7 × 2 8 2 9 6 0

then work out 2 times 37:

2 × 7 = 14:

 3 7 × 2 8 2 9 6 4 0 1
then

2 × 3 = 6:

 3 7 × 2 8 2 9 6 7 4 0 1

Finally, add these two rows of working out:

 3 7 × 2 8 2 9 6 7 4 0 1 0 3 6 1

The answer is:

 37 × 28   =   1036

## Explanation

To work out   37 × 28   you have separately multiplied
37 × 8     and     37 × 20.

In the second row you worked out 37 × 2 and this explains
the extra 0 you had to put at the end.

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