Lesson 3.4 · Counting to 100
Counting by ones to 100
You can count by tens to 100. Now let's count every number, one at a time, all the way to 100.
The counting pattern
After twenty, the numbers follow a pattern. Say the ten, then add one, two, three, and so on.
twenty, twenty-one, twenty-two, twenty-three, … twenty-nine
Then comes the next ten: thirty. And the pattern starts again: thirty-one, thirty-two, …
The hundred chart
A hundred chart shows every number from 1 to 100. Each row has 10 numbers. Read it left to right, then go down to the next row.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
|---|---|---|---|---|---|---|---|---|---|
| 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 |
| 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 |
| 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 |
| 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 |
| 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 |
| 61 | 62 | 63 | 64 | 65 | 66 | 67 | 68 | 69 | 70 |
| 71 | 72 | 73 | 74 | 75 | 76 | 77 | 78 | 79 | 80 |
| 81 | 82 | 83 | 84 | 85 | 86 | 87 | 88 | 89 | 90 |
| 91 | 92 | 93 | 94 | 95 | 96 | 97 | 98 | 99 | 100 |
Look down the last column: 10, 20, 30, … 100. Those are the tens!
After a 9 comes a new ten
When a number ends in 9, the next number is the next ten.
- After 29 comes 30.
- After 59 comes 60.
- After 99 comes 100.
Worked example: What comes next?
What number comes right after 46?
Say it: forty-five, forty-six, forty-seven. The answer is 47.
Worked example: Crossing a ten
What number comes right after 39?
39 ends in 9. So the next number is the next ten. Thirty-eight, thirty-nine, forty. The answer is 40.
Worked example: Fill in the blanks
Fill in the missing numbers: 67, 68, ___, ___, 71
Sixty-seven, sixty-eight, sixty-nine, seventy, seventy-one. The missing numbers are 69 and 70.
Common mistake
After 29, don't say "twenty-ten." Say thirty. Every time you reach a 9, the next ten comes next.
Practice
What number comes right after 23?
Type a number.
What number is missing? 50, 51, ___, 53
Type a number.
What number comes right after 79?
Type a number.
What number comes right after 49?
What number is missing? 83, 84, ___, 86, 87
Type a number.
What number comes right after 99?
Type a number.
Fill in the two missing numbers, in order: 57, 58, ___, ___, 61
Separate answers with commas, e.g. 2, -5