Numbers up to 100
Primary 1 · Mathematics
Numbers up to 100
Lesson 2 of 7
12 min
Let's begin
Umutoni packs maize cobs into sacks at home.
Each sack holds ten cobs. She has 7 full sacks and 9 loose cobs.
She drops in one more cob. “Seventy-ten!” she says.
That is not a number. Today you will cross every ten without slipping.
Start with 7 bundles. Add loose sticks one by one.
71, 72, 73, 74, 75, 76, 77, 78, 79
Now you hold 9 loose sticks. Add one more.
Nine and one more make a new bundle.
8 bundles and no loose sticks is 80.
There is no seventy-ten. Say eighty.
Point at each number and say it:
| 71 | 72 | 73 | 74 | 75 | 76 | 77 | 78 | 79 | 80 |
| 81 | 82 | 83 | 84 | 85 | 86 | 87 | 88 | 89 | 90 |
After 89 comes 90. Then the last row:
91, 92, 93, 94, 95, 96, 97, 98, 99
Write a number the way you build it.
Worked example
9 tens and 2 ones.
Step 1 Nine tens. Write 9.
Step 2 Two ones. Write 2 beside it.
Step 3 That is 92.
Careful! 902 is not ninety-two. 902 is far too big.
A number up to 99 uses only two digits.
99 is 9 bundles and 9 loose sticks.
It is packed full. You cannot write a bigger number with two digits.
Say the last five out loud: 95, 96, 97, 98, 99.
Tip
Nine and one more makes a bundle
When your loose sticks reach 9, stop. Tie them.
After 79 comes 80. After 89 comes 90.
If you hear yourself say “eighty-ten”, tie the bundle and say ninety.
Count from 71 and cross 79 into 80.
Do each one, then tap Show answer to check.
What comes after 79?
Answer: 80. One more stick makes ten loose sticks. Tie them. 8 bundles is 80.
What comes after 89?
Answer: 90. Not eighty-ten. 9 bundles is 90.
Write the numeral for 8 tens and 6 ones.
Answer: 86. Tens digit first, then the ones digit.
Which number is between 94 and 96?
Answer: 95. Count 94, 95, 96.
Gatete has 9 sacks of ten cobs and 4 loose cobs. How many cobs?
Answer: 94 cobs. 9 tens and 4 ones make 94.
What you learned today
Quick check
What number comes after 79?
