This Problem Set is a part of the Lesson 13, Unit 4, Grade 1. In this lesson, students apply the strategies of counting on and making ten to larger numbers, making a ten that is built on a structure of other tens. They use linking cubes as a concrete representation of the numbers, write a matching number sentence, and write the total in a place-value chart. As they add cubes, students see that sometimes a new ten can be made (for example, 33 + 7 = 40, or 4 tens).