Lesson 7

Workshop: Reasoning from Known Facts

Est. Class Sessions: 1

Summarizing the Lesson

Ask students to solve this problem:

Grace has 23 marbles and Jacob has 9 marbles. How many more marbles does Grace have than Jacob?

Ask a student to show how he or she could solve this problem using tens. Ask another student to show how he or she could solve this problem using thinking addition.

Select a few problems from the Workshop to discuss as a class. You might choose these problems to represent common areas of difficulty for students, or else areas where students made significant progress over the course of the lesson. Ask a few students to share their problems and solutions with the class.

Ask questions to help with comparisons and to stimulate discussion:

X
  • How did [student name] solve the problem?
  • Did someone use a different strategy or method?
  • Which strategy is best for this problem, using tens or thinking addition? Why?

Whatever problems they chose, all students solved Check-In: Questions 7–9, 14, and 18 on the Using Subtraction Strategies pages in the Student Activity Book.

X

Use Check-In: Questions 7–9, 14, and 18 on the Using Subtraction Strategies pages in the Student Activity Book to assess students' use of the using-tens and thinking-addition strategies to solve subtraction problems [E5].

Students can use some of the unsolved problems from the Workshop to provide additional targeted practice, if needed.

Student Guide:
Student Activity Book:
Master: