Jul05

Strategy for Multiplying by 2, 4, and 8

In this post, we are going to learn a very simple strategy for multiplying by 2, 4, and 8.

Strategy for Multiplying a Number by 2:

Multiplying by two is really easy, right? We just have to add the number to itself and we’ll get the answer.

For example:

2 x 48 = 48 + 48 = 96

We’ve doubled 48, and we end up with 96.

Strategy for Multiplying a Number by 4:

We know that 4 = 2 x 2, so in order to multiply by the number 4, we can multiply by two twice. (This is the same as doubling the number 2 times.)

For example:

13 x 4

We can write the 4 as 2 x 2, by doing this we have 13 x 2 x 2.

Let’s start doubling: 13 x 2 = 26

Now, we have to double it again: 26 x 2 = 52

What we did was 13 x 4 = 52
Strategy for Multiplying

Strategy for Multiplying a Number by 8:

The number 8 can be written as 8 = 2 x 2 x 2, so that means in order to multiply by 8, we can multiply by 2 three times. (This is the same as doubling the number 3 times.)

For example: 13 x 8

By writing 8 = 2 x 2 x 2, we actually have 13 x 2 x 2 x 2

Let’s start doubling: 13 x 2 = 26

And continue: 26 x 2 = 52

And let’s double for the last time: 53 x 2 = 104

What we essentially have done is 13 x 8 = 104

Strategy for Multiplying

If you want to practice this strategy with more examples, try Smartick for free.

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