Why does my child think the midpoint of (1, 2) and (5, 6) is (2, 2)?
Your child halves the difference of the coordinates instead of their sum to find a midpoint, such as (2, 2) for (1, 2) and (5, 6).
Why children do it
Halving the gap between the points says how far the midpoint is from each end, not where it is. To find where, add that to the first point. Or, more simply, average the coordinates: the midpoint is (3, 4).
How to help at home
Ask them to plot both points and their answer: is it really halfway between them?
The right way
Find the midpoint of (3, 4) and (9, 10).
- (3 + 9)/2 = 6Average the x's.
- (4 + 10)/2 = 7Average the y's.
- (6, 7)The midpoint.
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