multiplication


Long multiplication
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One digit easy

In this lesson we will explain how to multiply a multi-digit number by a one-digit number.

1. Write the numbers

You have to write the numbers in a drawing like this.

one digit multiplication

You first write the multi-digit number at the top, then you write the one-digit number under the units of the number at the top.

Example

one digit multiplication example

Training

Select the correct drawing to multiply 1357 by 9.

one digit multiplication example one digit multiplication example one digit multiplication example


2. Multiply the Units

You multiply the one-digit number by the Units of the top number.

If the result has only one digit (example : 3×2=6) it is an easy multiplication.
In such a case you write the result under the line, under the one-digit number.

Example

one digit multiplication example

Training

Which digit do you write under the 4?

one digit multiplication



3. Multiply the tens

You multiply the one-digit number by the tens of the top number.

If the result has only one digit you write it under the line, at the left of the number you found out at step 2.

Example

one digit multiplication example

Training

Which digit do you write left of 6?

one digit multiplication



4. Multiply the hundreds, the thousands,...

You do the same with the hundreds of the top number, with the thousands...

When there are no more digit to multiply you can read the final result of the multiplication under the line.

Example

one digit multiplication

Training

What is the final result of the multiplication below?

one digit multiplication