Lesson 13 Analyze Addition Mistakes

    • Let’s use place value strategies to add decimals.

Warm-up Estimation Exploration: Many Places

Record an estimate that is:

too low

about right

too high

Activity 1 Compare Calculations

  1. Find the value of . Explain or show your reasoning.

  2. Elena and Andre found the value of . Who do you agree with? Explain or show your reasoning.

    Elena's and Andre's addition algorithms and reasoning.

Activity 2 Same Digits, Different Sums

Find the value of each expression. Explain or show your reasoning.

Practice Problem

Problem 1

Find the value of the expression .