# Lesson Plan

## Using Guess, Check and Revise

Main Subject Area: Mathematics

Duration of Lesson:  45 minutes

Keywords:

• Guess and Check
• Math Strategies
• Problem Solving

Brief Description:

Students will answer coin related math questions using the guess, check and revise process for problem solving.

National Standard(s):

• Problem Solving
• Number and Operations

Additional Subject Area Standard(s):

Objectives:

Students will determine the information they need to solve a problem.

Students will use the guess and check method to solve their problem.

Students will test their answer using this method with real coins.

Materials (online):

Materials (offline):

Math Problem Solving Strategies (examples can be found online at http://mathcounts.org/Problems/strategies.html, http://www.fcps.k12.va.us/DeerParkES/kids/diane/Math/tenstrat.htm, or other similar web sites that explain these strategies)

Math Journals

Coins Used in Lesson:

Currently circulating U.S. coins

Procedures (online):

Procedures (offline):

1. Explain to students that there are many different strategies for solving math problems. It is important to know the strategies, and also know when to choose the right strategy. Today they are going to examine the Guess, Check and Revise method.

2. First, solve this problem together as a class: How many different combinations of the coins (nickels, dimes and quarters) can make 50 cents? You must use at least one of each coin.

3. Have students make a guess and write several guesses on the board.

4. Write out the specifics of the problem:

Need to make 50 cents

Can only use nickels, dimes and quarters

Must use at least one of each coin

5. Work with your students to develop a chart with the possible solutions. There will only be two solutions for this problem (1 quarter 2 dimes and a nickel; 1 quarter, 1 dime and 3 nickels). Students can then revise their answer based on the chart.

6. Now give students a problem to solve on their own. They can use the same method you did as a class. They can record the steps in their math journal. Here is a sample problem:

How many different combinations of the coins (nickels, dimes and quarters) can make \$2.25? You must use 17 coins.

Assessment / Evaluation:

Students can be evaluated on the steps they wrote for solving the problem. They should include the problem, the conditions, their guess, their chart or illustration for checking, and their revised answer.

Differentiated Learning Options:

Students can create their own problems involving coins and combinations for a certain total and share them with each other. Students can use real coins to check their guesses.