Lucas sits beside his friend Ben during maths. Their teacher writes some sums on the board. She asks Lucas to come forward and try one. He picks up a pen and writes the answer. The teacher tells him that he is right. Lucas smiles as he returns to his seat. Beside him, Ben looks worried about his work. He tells Lucas that he does not understand. Lucas moves closer so they can work together. He draws ten circles on a sheet of paper. Then he crosses out three of the circles. He asks Ben how many circles are left. Ben counts carefully and says there are seven. Now he is ready to try the next sum alone. He gets it right and smiles at his friend.