For children, games can give immediate value to what children know and are learning. The nature of Gordon's Games allows children, from about age four to nine, to use their knowledge of simple arithmetic as they work out their own moves and check their opponent's moves. I made my cards out of Bristol board sheets, a thick, stiff paper product that felt pen ink will not show through. The cards don't have to be fancy but you shouldn't be able to look at the backs and easily identify the card.
Children enjoy the games.
They don't see them as work, or drill activities. They ask to be allowed to play them. Up until 1968 I taught classes from Grade 4 to 7. Since then I have taught Kindergarten to Grade 3, ages 4 to 9. The games were first started in the 70's.