A game inspired by the Activity of Montessori called “Couples of 10”, to teach the child how to count up to 10 and make the first simple prostheses. The set contains 11 cards to count with your fingers, 11 cards with quantities, 10 cards with numbers, 9 “pairs of 10” cards and a tab for additions. At first the child is asked to combine hand cards, quantity cards and numeric symbols, to learn how to count up to 10. Then, thanks to the “pairs of 10” cards, he can have fun looking for all the combinations of quantities that have the sum of 10. So he will be led spontaneously to carry out his first mathematical operations.