Most 1st grade teachers employ little tricks to help kids master addition and subtraction. They'll grab almost any object to show how to get 3 and 6 to make 9. They generally won't suggest counting on fingers, which can become a tough-to-break habit later. But they have other time-tested learning aids, such as making tally marks with pencil and paper (a series of parallel lines, with the fifth line in every "bundle" crossing the other lines diagonally), and counting forward for addition and backward for subtraction.