Multiplying by 8

In this lesson, you're going to learn how to multiply by 8.Β

But what does it mean to multiply by 8?

**Multiplication **is repeated addition.

Let's say you invite 8 friends over to play.

You're thinking of baking cookies.

If you want each friend to have 3 cookies, how many cookies do you need to prepare?

You'll find the answer if you multiply by 8. π

**Multiplying by 8 **is the same as skip counting by a number 8 times. Or you can also think of it as adding 8 equal groups.

So what's 8 x 3?

Let's skip count 3, eight times:

3, 6, 9, 12, 15, 18, 21, 24

So 8 x 3 = 24!

π€ **Tip:** if skip counting by one factor is too hard, try the other factor.Β

Let's try skip counting by 8, three times:

8, 16, 24!

Again we see that 8 x 3 = 24!

Isn't it helpful to know how to multiply by 8? π

This is the multiplication table for 8.

Did you notice **a pattern?**

Look at the answers for 1 to 10.

π The digits in the Ones place **go down by 2.**Β

It starts from 8 and it goes all the way down to 0.Β

Then, it starts back at 8, and goes all the way down to 0 again. π

Did you notice **another pattern?**

That's right!

π All the answers are **even numbers.**

This might be the first time that you'll try to multiply by 8.

You may think that it's hard, but it really isn't.Β

Here's a secret trick that will help make multiplying by 8 easy. π

When you need to **multiply by 8,** just **double a number 3 times.**

**To double a number **means to **multiply it by 2.**

This works because 2 x 2 x 2 = 8!

Let's say you need to multiply this:

4 x 8 =?

**π First,** multiply 4 by 2.

4x2=8

**π Then,** multiply your answer by 2 again.

8x2=16

π **Finally,** multiply your answer by 2 for the third time.

16x2=32

The last number you get is your answer.Β

32! π

Let's try another example.

Multiply this:

8 x 5=?

What's your answer?

Great work!

It's 40! π

Which way did you use to figure out the answer? π

Remember that the multiplication table is your most useful tool.

Now, it's time to try practice. πͺΒ

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