Usually when you do expressions involving subtraction you can do Keep, Change ,Change That means you keep the sign of the first number and change the other two signs. It is best you rewrite the expression to addition because a lot of people don't do well with subtracting .
Chocolate thickshakes will cost $5 and fruit smoothies will cost $3. Let's say the cost of chocolate thickshakes are x and the cost of fruit smoothies are y.
