Show the children how they can scoop sand into a cup using a tablespoon.
Pair each child with a partner. Invite each pair to have one partner spoon the sand into a cup using the tablespoon while the second partner counts.
As the second partner counts each spoonful, have them keep track by creating a cube tower by adding a cube for each spoonful of sand.
When the cup is filled, the children can count the cube towers to remind them of how many spoonfuls of sand they used to fill the cup.