This Problem Set is a part of the Lesson 1, Unit 5, Grade 2. In this lesson, students apply knowledge of place value to add and subtract numbers up to 1,000. Using sentence frames and place-value disks, they relate 100 more, 100 less, 10 more, and 10 less to addition and subtraction. For example, 290 - 100 is 2 hundreds 9 tens minus 1 hundred.