Knowing how far away to get from the line before going up. They wanted to count at an angle.

Did similar with Y11. Some found it difficult to see the distances horiz and vert but drawing in all steps in the ‘staircase’ seemed to fix it. Also picturing staircases where depth of step stays the same but steeper staircases go up more each step.

Parallelograms was chop off one end to make a right angle and stick to other side to fill the gap. Checked that it only fit the gap when parallel sides.

Chopped a rectangle out of the middle and made one triangle from the two ‘ends’. Even when we weren’t sure about the base length of each end we knew the total base was the difference between the length of the two parallel sides - although I didn’t say it like that.

Height and that had to be ‘straight up’ from the base not ‘wonky’. Practised identifying these explicitly.

Then triangles that they had to turn into parallelograms. Seems to stick for mocks they just did.

Taught same last term to foun Y11 I took over this year. Told them we can only be sure about the number of squares in a rectangle so we always have to find the rectangle. Then parallelograms- made them into rectangles every time. Practised finding perpendicular lengths when distractions were added.

Did they do enough forwards to see the backwards?