This Fluency Activity is a part of the Lesson 5, Unit 3, Grade 1. Practice with counting forward and backward by tens and ones strengthens students' understanding of place value. Counting by twos and fives builds students' ability to count on or back and strengthens addition and subtraction skills. Repeat the Happy Counting activity from Lesson 2. Choose a counting pattern and range based on the skill level of the class. If students are proficient with counting by ones, twos, fives, and tens up to 40, start at 40, and quickly go up to 80.