Numbers up to 50
Primary 1 · Mathematics
Numbers up to 50
Lesson 2 of 6
12 min
Let's begin
Mutesi helps her aunt sell avocados in the Kigali market.
They pack ten avocados in each basket. Two baskets are full.
Five more avocados sit on the cloth. Today you will name every number from 21 to 30.
Two bundles of ten make 20. We say twenty.
20 has 2 tens and 0 loose ones.
Now add loose ones, one at a time.
2 tens and 1 one make 21. We say twenty-one.
2 tens and 2 ones make 22. We say twenty-two.
Every name starts with twenty. Then you say the loose ones.
| Number | We say |
|---|---|
| 21 | twenty-one |
| 23 | twenty-three |
| 25 | twenty-five |
| 28 | twenty-eight |
| 29 | twenty-nine |
| 30 | thirty |
Mutesi has 2 full baskets and 5 loose avocados. That is 25 avocados.
Worked example
write twenty-five.
Step 1 Hear the tens. Twenty means 2 tens. Write 2.
Step 2 Hear the ones. Five means 5 ones. Write 5 beside it.
You get 25.
Careful! Some children write 205. That number is two hundred and five. It is much too big for a basket of avocados.
A number up to 50 uses only two digits. One for bundles. One for loose ones.
12 is 1 ten and 2 ones. We say twelve.
20 is 2 tens and 0 ones. We say twenty.
The words sound alike. The numbers are not the same.
Say them slowly: twelve... twenty. Count the bundles each time.
29 is 2 bundles and 9 loose ones.
Add one more. Nine loose ones and one more make ten. Tie them!
Now you hold 3 bundles. That is 30.
Tip
Tens first, then the loose ones
You hear twenty first. So you write the 2 first.
Two digits only. One for the bundles, one for the loose ones. Never three.
Two full tens and some loose ones: 20 to 29.
Write your answer, then tap Show answer to check.
Write the number for twenty-three.
Answer: 23. Two tens first, then three ones.
Ishimwe has 2 bundles of ten sticks and 8 loose sticks. How many sticks?
Answer: 28. Count 10, 20, then on: 21, 22, 23, 24, 25, 26, 27, 28.
What number comes after 29?
Answer: 30. The nine loose ones and one more make a new bundle.
Which is bigger, 12 or 20?
Answer: 20. It has 2 bundles. 12 has only 1 bundle.
Say what 27 is made of.
Answer: 2 tens and 7 ones.
What you learned today
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