Why does my child write 45 000 as 4.5 × 10³?
Your child counts the zeros instead of the places the decimal point moves, such as 45 000 = 4.5 × 10³.
Why children do it
Counting the zeros works for 1000, which is 10³, so it seems like a shortcut. But the power of 10 counts how many places the decimal point moves to give a number from 1 up to 10. From 45 000 to 4.5 is 4 places, so it's 4.5 × 10⁴.
How to help at home
Ask them to count how many places the decimal point moves to give a number between 1 and 10.
The right way
Write in scientific notation: 2800
- 2800 = 2.8 × 10002.8 is between 1 and 10.
- 2.8 × 10³1000 is 10³: the point moved 3 places.
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