Why does my child think log₂ 8 = 4?
Your child divides to work out a log, such as log₂ 8 = 8 ÷ 2 = 4 instead of 3.
Why children do it
With two numbers in front of them, children divide. But a log asks for a power: log₂ 8 is the power of 2 that makes 8, and 2 × 2 × 2 = 8, so it's 3. Saying it aloud as a question, '2 to what power makes 8?', helps.
How to help at home
Ask them to say it as a question: 2 to what power makes 8? Then count: 2, 4, 8.
The right way
Work out the logarithm of 8 to base 2.
- 2³ = 82 to the power 3 makes 8.
- 3So the log of 8 to base 2 is 3.
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