Activities emphasize one or the other of these competencies. That is, the relator idea might be developed by filling a container with different size units, children generalize that the larger the unit, the fewer are needed. Challenge them to make a multiplicative relationship, starting with doubling (e.g., "This scoop holds twice as much, so we'll only need half as many").  The repeater idea is simply that repeating a unit (like a scoop) gives the same result as having…that many scoops! With cubes in a box, children learn that they can use one cube to figure out how many in a row, how many rows (a layer), and how many layers on top of each other (the height).