Division as sharing
Deal cookies onto plates or pack them into bags, find the leftovers, and see how division undoes multiplication.
Standards: 3.OA.A.23.OA.B.6
1Wonder
Grandma baked 12 cookies for you and your 2 cousins. How can you share them so that nobody complains? And what if she had baked 14?
2Explore
This activity needs a bigger screen
Turn your phone sideways, or open this lesson on a tablet or computer. The explanation and quiz below work here.
- Share 12 cookies on 3 plates. Press Deal them out. How many does each plate get?
- Now try 14 cookies on 3 plates. What happens to the extra cookies?
- Switch to Make groups. Put 12 cookies in bags of 3. How many bags do you fill?
- Compare: 12 shared on 3 plates and 12 in bags of 3. What do you notice about the numbers?
3Explain
Sharing equally
Deal 12 cookies onto 3 plates, one at a time, until they are all gone. Each plate gets 4. We write 12 ÷ 3 = 4.
total ÷ number of groups = size of each group
Division shares a total equally, or finds how many equal groups fit. It is the opposite of multiplication: 12 ÷ 3 = 4 because 3 × 4 = 12.
4Practice
15 marbles are shared equally by 3 children. How many does each child get?
5Recap
- Division shares a total into equal parts, or finds how many equal groups fit.
- 12 ÷ 3 = 4 can mean 3 plates of 4, or 4 bags of 3.
- Division undoes multiplication: think “3 × ? = 12”.
- What does not fit is the remainder.