This Problem Set is a part of the Lesson 10, Unit 1, Grade 1. In this lesson, students use 5-group cards to solve "put together with result unknown" problems based on stories and pictures (for example, "In a first-grade classroom, 5 students are sitting down and 2 students are standing. How many students are there in all?"). They use pictures and 5-group cards to represent the quantities involved, and count on to find the total.
