Students put all their addition and subtraction skills together to solve equations.

Louis E. Raths, The Grade-Placement of Addition and Subtraction of Fractions, Educational Research Bulletin, Vol. 11, No. 2 (Jan. 20, 1932), pp. 29-38 ...

Relating addition and subtraction and playing the game BUMP; counting down.

Twenty-four first-grade children were asked to write number sentences and select appropriate alternative number sentences for addition and subtraction word problems. Responses were qualitatively ...