Numbers up to 50
Primary 1 · Mathematics
Numbers up to 50
Lesson 1 of 6
10 min
Let's begin
Mugisha helps his father gather sticks for the fire.
Ten sticks make one bundle. He ties each bundle with dry grass.
Soon five bundles lie in a row on the ground. Today you will count in bundles of ten.
Count ten sticks: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10.
Now tie them together. You made a bundle.
A bundle is one thing you can hold. Inside it are ten sticks.
One bundle is 10. Two bundles are 20.
Say the bundles out loud with me: 10, 20, 30, 40, 50.
| Bundles | Sticks |
|---|---|
| 1 | 10 |
| 2 | 20 |
| 3 | 30 |
| 4 | 40 |
| 5 | 50 |
Five bundles are 50 sticks. Mugisha carried 50 sticks home!
Try it with beans. Put ten beans in a small bag. Then fill more bags.
Worked example
37 + 10.
37 is 3 bundles and 7 loose sticks.
Step 1 Add one whole bundle. Do not touch the loose sticks.
Step 2 The loose sticks stay the same: 7.
Step 3 The bundles climb by one: 3 bundles becomes 4 bundles.
4 bundles and 7 loose sticks make 47.
37 + 10 = 47
Careful! Some children answer 38. That is one more stick. You needed one more bundle.
Say this chant out loud:
17, 27, 37, 47.
Look at the last digit. It is 7 every time.
Only the bundle digit climbs. Now chant this one: 12, 22, 32, 42.
Tip
One more bundle, not one more stick
When you add ten, hold your finger on the last digit. It does not move.
Only the bundle digit climbs: 3 bundles, then 4 bundles.
Sing the tens: 10, 20, 30.
Do each one, then tap Show answer to check.
Count in tens: 10, 20, 30, ___, 50.
Answer: 40. That is four bundles of ten.
24 + 10
Answer: 34. The ones stay 4. Two bundles becomes three bundles.
8 + 10
Answer: 18. The ones stay 8. Now there is 1 bundle.
Umutoni ties 4 bundles of ten sticks. How many sticks?
Answer: 40. Count the bundles: 10, 20, 30, 40.
Gatete has 31 beans. He drops in 10 more. How many now?
Answer: 41. The ones stay 1. Three bundles becomes four bundles.
What you learned today
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