## Topic:

Problem solving process: check

**Standards**:

MCC2.OA.1. Use addition and subtraction within 100 to solve one- and two-step word problems involving situations of adding to, taking from, putting together, taking apart, and comparing with unknowns in all positions., e.g., by using drawings and equations with a symbol for the unknown number to represent the problem.

**Essential Que****stion**:

How do mathematicians check their work?

## Duration:

About 1 hour

## Materials:

chart with problem solving steps, marker, math games, word problems

## Overview or notes pertaining to lesson:

Students will learn the last step of the problem-solving process: Check

## Mini Lesson:

The past few days we have talked about the problem solving process: Read and Understand, Plan, Solve. Today we are going to do the last step in the process: Check. Once you solve a problem, you’re not done. You need to check your work and make sure you have done everything correctly. To check you can solve the problem in a different way or look back at your work and look back at what the problem says.

## Guided Practice:

Solving a different way probably won’t work very well with this type of problem. Practice with Lynn’s Ladder, looking back at what the story says, and matching it to the work we have done to make sure everything looks correct. Then check the sentence we wrote as our answer to make sure we stated the correct answer and that it makes sense. Math always needs to make sense.

## Independent Practice:

Group 1: pattern activity with base ten blocks from day 7, Group 2: teacher-allow students to practice the “Plan” step with a different exemplar problem (use the same one you used in the last lesson), Group 3: tic tac toe, Group 4: odd/even game. After about 10 minutes, clap for attention, clean up, and rotate. Remember to correct behaviors immediately and praise good behaviors. Feel free to switch up any of those math games with others at any time.

## Closing:

Journal Entry: Review all 4 problem solving steps.