This Fluency Activity is a part of the Lesson 10, 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 strengthens addition and subtraction skills. Repeat the Happy Counting activity from Lesson 2. Choose a counting pattern and range based on the class's skill level. If students are proficient with counting by ones, twos, fives, and tens to 40, start at 40 and go to 80.