Topic 3 of 8
Skip counting by 5s, 10s, and 100s
Step 4 · Place value to 1,000 topics
Count in steps of 5, 10 and 100 from any number, and spot the patterns in the digits.
Counting by 5s
Counting by 5s says every fifth number: 5, 10, 15, 20, 25, 30. The ones digit takes turns: 5, 0, 5, 0.
Hands are a good model: each hand has 5 fingers, so 4 hands have 20 fingers. Nickels are worth 5 cents each, so 3 nickels are 15 cents.
Counting by 10s
Counting by 10s from a tens number goes 10, 20, 30. From any other number, the tens go up by one and the ones stay the same: 37, 47, 57, 67.
| Start | Next | Next | Next |
|---|---|---|---|
| 30 | 40 | 50 | 60 |
| 37 | 47 | 57 | 67 |
| 185 | 195 | 205 | 215 |
Counting by 100s
Counting by 100s goes 100, 200, 300 … 900, 1,000. From another number, only the hundreds digit changes: 250, 350, 450.
Example: Hundreds only
Count by 100s from 140. What are the next three numbers?
- Add a hundred each time.
- The tens and ones stay 40.
Answer240, 340, 440
Counting back works too: by 10s from 90 is 80, 70, 60; by 100s from 700 is 600, 500, 400.
Try it yourself
Work each one on paper first, then open the answer to check.
Count by 5s from 5 to 50.
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5, 10, 15, 20, 25, 30, 35, 40, 45, 50.
Count by 10s from 23. What are the next three numbers?
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33, 43, 53.
Count by 100s from 300 to 900.
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300, 400, 500, 600, 700, 800, 900.
How many cents are 6 nickels?
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30 cents: 5, 10, 15, 20, 25, 30.
What comes next: 575, 580, 585, _?
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590: counting by 5s.