One ladder. Adding is a length, multiplying is an area, cubing is a volume — and Pythagoras is where length and area meet.
Touch the corners, name the shape, build one yourself — triangles, rectangles, angles, symmetry.
Cut a block of dots into equal parts and check by counting: two halves of 24 are 12 each.
(3, 5) is three dots along and five dots up. Read a dot's numbers, put a dot there, draw shapes.