This simple activity is designed to give primary students a challenge by adding amounts of money. Students will be expected to use a key to identify buttons and designate a price for each one. Differentiation may occur if a teacher gives lower ability students manipulatives or allows the students to color the buttons accordingly first. Another option would be to use calculators. Primary students who need a challenge may complete the activity as is or may be expected to give a very detailed explanation of how the answer was determined.