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Math · Grade 3 Math

Chapter 1: Multiplication and Division as Equal Groups

Multiplying by 2, 5, and 10

The three easiest tables, and why they are easy.

Lesson
6
Time
About 12 minutes
0 of 8 done

Step 1: Let's Learn

Read it, or press Listen and follow the words.

The 2 times table is doubling

You already know your doubles from Grade 2. 7 × 2 is just double 7.

The 10 times table

Every answer ends in 0. 6 × 10 = 60, because it is 6 tens.

The 5 times table

Every answer ends in 5 or 0. And 5 is half of 10, so 6 × 5 is half of 60.

Why these three come first

The 2s are doubles, which you already knew in Grade 2. The 10s just put a zero on the end. The 5s are half the 10s. All three connect to something you can already do quickly, which is why they are learned before the rest.

Why multiplying by ten adds a zero

7 × 10 = 70 because seven tens is seven in the tens place with nothing in the ones. The digit has moved one column to the left and a zero holds its old place open. Saying "add a zero" is a fine shortcut as long as you know why it works — it will stop working when you meet decimals.

Fives are half of tens

8 × 5 must be half of 8 × 10 = 80, so it is 40. Every answer in the 5 times table ends in 0 or 5, alternating. Two independent ways to reach the same fact makes it far more likely to stick.

Step 2: Try It Yourself

Tap and try it out.

Set the columns to 2, 5, or 10 and step the rows through.

5 + 5 + 5 + 5 + 5 + 5 = 30

6 × 5 = 30

6 rows of 5 makes 30.

Step 3: Watch an Example

One step at a time.

Watch Leo Halve a Ten

Leo is asked for 8 × 5.

  1. Step 1

    He does not count in fives all the way up.

Step 4: Your Turn

Practice makes it stick.

The Coins

Problem 1 of 2

Ana has 7 five-pence coins. How many pence is that?

pence

The Boxes

Problem 2 of 2

9 boxes each hold 10 pencils. How many pencils?

pencils

Twos, Fives, Tens

1 of 4

7 × 2 = ?

2 of 4

6 × 5 = ?

3 of 4

8 × 10 = ?

4 of 4

9 × 5 = ?

Step 5: Quick Check

Show what you know.

Question 1 of 2

7 × 5 = ?

Question 2 of 2

What do all the answers in the 10 times table end in?

What You Learned

  • The 2 times table is doubling.
  • The 10 times table always ends in 0.
  • A five is half of a ten, so halve the ten answer.