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Math · Grade 3 Math

Chapter 1: Multiplication and Division as Equal Groups

Multiplying and Dividing by 3 and 4

Two more tables, built from ones you know.

Lesson
8
Time
About 13 minutes
0 of 8 done

Step 1: Let's Learn

Read it, or press Listen and follow the words.

Fours are double doubles

7 × 4 is double 7 doubled: 14, then 28.

Threes from twos

7 × 3 is 7 × 2 plus one more 7: 14 and 7 makes 21.

Dividing too

28 ÷ 4 asks what times 4 makes 28. Same facts, read the other way.

Building the 3s and 4s from the 2s

The 4 times table is the 2 times table doubled: 6 × 4 is 6 × 2 = 12, doubled to 24. The 3 times table is the 2s plus one more group: 6 × 3 is 6 × 2 = 12, plus 6, giving 18. Every new table can be reached from an older one.

Patterns to lean on

Every answer in the 4 times table is even, and every one is double an answer in the 2s. The 3s alternate odd and even: 3, 6, 9, 12, 15, 18. Their digits also add up in a repeating cycle — 1+2 for 12, 1+5 for 15, 1+8 for 18 gives 3, 6, 9 again.

From working out to knowing

Building a fact from a known one is a good bridge but not the destination. Facts you rebuild every time slow down every longer calculation later. Use the building strategies while you learn, and keep practising until the answers simply arrive.

Step 2: Try It Yourself

Tap and try it out.

Set the columns to 3 or 4 and work up through the rows.

4 + 4 + 4 + 4 + 4 + 4 + 4 = 28

7 × 4 = 28

7 rows of 4 makes 28.

Step 3: Watch an Example

One step at a time.

Watch Leo Double Twice

Leo is asked for 8 × 4.

  1. Step 1

    He doubles 8 to get 16.

Step 4: Your Turn

Practice makes it stick.

The Tables

Problem 1 of 2

6 tables each seat 4 people. How many people can sit down?

people

The Tricycles

Problem 2 of 2

9 tricycles each have 3 wheels. How many wheels?

wheels

Threes and Fours

1 of 4

6 × 3 = ?

2 of 4

7 × 4 = ?

3 of 4

24 ÷ 3 = ?

4 of 4

36 ÷ 4 = ?

Step 5: Quick Check

Show what you know.

Question 1 of 2

8 × 3 = ?

Question 2 of 2

What is multiplying by 4 the same as?

What You Learned

  • Fours are double doubles.
  • Threes are twos plus one more group.
  • Division uses the same facts backwards.