1.1.4

Counting in Powers of 10

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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.
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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.

Jump to other topics

1Year 5 - Number

2Year 5 - Measurement

3Year 5 - Geometry

4Year 5 - Statistics

5Year 6 - Number

6Year 6 - Ratio & Proportion

7Year 6 - Algebra

8Year 6 - Measurement

9Year 6 - Statistics

9.1Displaying Data

9.2Averages

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