multiplication


Long multiplication
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One digit difficult

1. Introduction

We have seen how do multiply a multi-digit number by a one-digit number but we didn't see the case of the result of a multiplication has two digits.

Example

long multiplication example

When you multiply 3 by 3 the result has only one digit (9).
You write it under the line.

After that, you have to mutliply 3 by 4.
As the result (12) has 2 digits you don't write it under the line.

2. Method

In case of the result of a multiplication has two digits you just write the Units of this number under the line.

long multiplication example

At the same time you carry the tens.
That mean that you write it somewhere at the top-right of the drawing.

long multiplication example

Training

We would like to multiply 4444 by 4.

long multiplication example

Digit in the green box :
Digit in the blue box :


After that you have to add the carry number with the result of the next multiplication.

Example

long multiplication example

long multiplication example

Training

Write the two first digits you find when you multiply 4567 by 8.

long multiplication example




Finally you multiply by the hundreds, the thousands...Each time you add the number previously carry.

When there is no more digit to multiply by, you read the final result under the line.

Training

Write the result of 945×3.

long multiplication example