Why does my child get the wrong sign for a gradient?
Your child takes the points in a different order on the top and the bottom of the gradient, which changes its sign.
Why children do it
Finding a gradient takes one point from the other, on the top and on the bottom. If the points are taken in a different order on the top than on the bottom, the sign flips. Labelling the points 1 and 2, and always taking point 1 from point 2, keeps it right.
How to help at home
Ask them to label the points 1 and 2, and take point 1 from point 2 on the top and the bottom.
The right way
Find the gradient of the line through (1, 2) and (3, 8).
- 8 − 2 = 6The change in y.
- 3 − 1 = 2The change in x, with the points in the same order.
- 6 ÷ 2Rise over run.
- 3The gradient.
Find out where your child is
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Start the free checkRelated mistakes
- Why does my child divide the wrong way to find a gradient?
- Why does my child think the midpoint of (1, 2) and (5, 6) is (6, 8)?
- Why does my child think the midpoint of (1, 2) and (5, 6) is (2, 2)?
- Why does my child think the distance from (1, 2) to (4, 6) is 25?
- Why does my child think the distance from (1, 2) to (4, 6) is 7?
- Why does my child plot (3, −2) above the x-axis?
- Why does my child write (−4, 3) for the point (3, −4)?