Counting in Powers of 10
Maths: Year 5 & 6 National Curriculum, topic 1.1.4
Counting Forwards & Backwards in Powers of 10
You can count in powers of 10. Counting in powers of 10 is when you count forwards or backwards in 10s/100s/1000s etc.
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Adding and subtracting 1,000
- In order to add or subtract 1000 from 1,111,111, you need to focus on the thousands column.
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Add 1,000
- If I add 1000, my number becomes 1,112,111.
- 1,111,111 + 1,000 = 1,112,111
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Subtract 1,000
- If I subtract 1,000, you need to change the thousands column.
- If I subtract 1,000, my number becomes 1,110,111.
- 1,111,111 − 1,000 = 1,110,111
Counting Forwards & Backwards in Powers of 10
Adding and Subtracting in powers of 10 will usually only affect the column you are adding and taking away from. But adding or subtracting powers of 10 will sometimes affect other columns.
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Adding example
- 695 + 10 = 705
- In this example, when I add 10 to 695, some of the 10 I'm adding takes me into the next hundred.
- Both the 'tens' and 'hundreds' column are affected because the 10 I add has added enough to take my number into the next 'hundred'.
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Subtracting powers of 10
- Subtracting 10 from some numbers can also affect the 'hundreds' column in the same way.
Subtracting example
- 704 − 10 = 694
- In this example, when I subtract 10 from 704, some of the 10 I'm subtracting takes me into the hundred below.
- Both the 'tens' and 'hundreds' column are affected because the 10 I subtract has taken enough away take my number into the 'hundred' below.
Test yourself on Counting in Powers of 10
What is 51,431 + 100?
What is 8,213 − 100?
What is 17,062 − 10,000?
What is 502 − 10?
What is 902 + 100?