Lesson 1

First Names

Est. Class Sessions: 3

Daily Practice and Problems

Teacher Notes
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TIMS Task

Asking students to disprove an incorrect answer is a good technique for eliciting explanations and not just answers. Students can use manipulatives or draw pictures to show that 17 − 9 = 8 or use the fact that 9 + 8 = 17. Students may also use a ten: 17 − 10 is 7, so 17 − 9 is one more, or 8.

D. Mike and Terrence Smart

Mike Smart is helping his brother, Terrence, with his homework. Terrence says that 17 − 9 is 9. Mike is trying to show Terrence that he is wrong. How do you think Mike should show Terrence his mistake?