Division as Equal Groups: How Many Groups? (3rd Grade)

What is it?

Division has two meanings. In the sharing lesson, you know how many groups and find how many go in each. This lesson is the other meaning: you know the size of each group and find how many groups you can make. 15 ÷ 3 asks "how many groups of 3 make 15?" Your child takes 3 counters at a time, puts each group on a plate, and counts the plates.

Step by step: 15 ÷ 3

1. 15 ÷ 3 asks: how many groups of 3 make 15?
2. Take 3 counters at a time.
3. Put each group of 3 on a plate until all 15 are used.
4. Count the plates: 1, 2, 3, 4, 5. So 15 ÷ 3 = 5.
5. Check with times: 5 groups of 3 is 15.

Common mistakes

• Answering with the group size (3) instead of the number of groups (5).
• Leaving counters out. Keep making groups until none are left.
• Making a last group that is too small. Each group must have exactly 3.

Your turn

The lesson ends with a problem to try. Pause and let your child work it out before you check.

How many groups of 4 make 12? (12 ÷ 4)

Answer: 3. Make groups of 4 until all 12 are used, and there are 3 groups. Check: 3 × 4 = 12.

Practice at home

Count out a pile of small objects and pick a group size. Scoop groups of that size into cups until the pile is gone, then count the cups. Ask the same question two ways: "How many groups of 4 make 20?" and "20 ÷ 4 is what?"