Why does my child divide the wrong way to find a gradient?
Your child divides the change in x by the change in y to find a gradient, such as 2/6 for the line through (1, 2) and (3, 8).
Why children do it
A gradient is how far a line rises for each step across: the change in y divided by the change in x. Children who put x first, as coordinates are written, divide the wrong way, and get a much flatter or steeper line than the real one.
How to help at home
Ask: how far up for each step across? The rise goes on top.
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
A free maths check, in about 15 minutes, shows what your child knows and the mistakes they make. No sign-up.
Start the free checkRelated mistakes
- Why does my child get the wrong sign for 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)?