This Problem Set is a part of the Lesson 14, Unit 4, Grade 1. In this lesson, students use arrow notation to reach the next ten, and then add the remaining amount when adding across ten. For example, when adding 28 + 6, students recognize that they started with 2 tens 8 ones and, after adding 6, had 3 tens 4 ones. Throughout the lesson, students use number bond notation to represent how they are breaking apart the second addend to make the ten.