Solving one-step algebraic expressions: x + a = b

In this section, we are given models of cups and counters and asked to write the one-step equations represented by these models. Then, we are asked to determine the number of counters needed in each cup to make the equations true. We were first introduced to cup and counter models the section on evaluating algebraic equations. Along with writing equations using given models, in this section we are given one-step algebraic equations and asked to solve these equations for the given variables. Finally, we are presented with a situation in a world problem and given an equation to model this situation. We are asked to determine what the variable in the equation represents, given the situation.