The pattern
Work out where the pieces land after a fold, cut or stack.

A shape gets folded, cut or rearranged, and the answer comes from tracking where each piece lands rather than from a formula. A fold reflects one part onto another, so an angle either side of the crease survives unchanged. A strip of three squares folded into a cube always sends the two ends to opposite faces.
Words like 'folded', 'cut along the dotted line' or 'stacked' appear beside a shape, and the question asks for a length or angle that only makes sense once the pieces are in their new positions.
Children try to calculate the answer before working out where the pieces actually end up, skipping the visualisation step that the whole question depends on.
All the problem patterns → · the revision list
All 33 patterns, one to a page — the 19 behind Primary 5 and 6 word problems, and the skills the younger years are built on. The bar model, how to spot it in the question, and the mistake children make. A booklet you can print. Free.
A PDF, and a note when new solutions go up.