This Fluency Activity is a part of the Lesson 15, Unit 5, Grade 2. This activity uses dimes and pennies as abstract representations of tens and ones to help students become familiar with coins, while simultaneously providing practice with counting forward and back by tens or ones. First minute: Place and take away dimes in a 5-group formation as students count along by ten. Second minute: Begin with 2 pennies. Ask how many ones there are. Instruct students to start at 2.