A Lesson Plan for A Chair for My Mother

**Data Collection
Addition
Estimation
Money, Coins**

Represent and interpret data.

CCSS

1.OA.7. Understand the meaning of the equal sign, and determine if equations involving addition and subtraction are true or false. For example, which of the following equations are true and which are false? 6 = 6, 7 = 8 – 1, 5 + 2 = 2 + 5, 4 + 1 = 5 + 2.

1.NBT.3. Compare two two-digit numbers based on meanings of the tens and ones digits, recording the results of comparisons with the symbols >, =, and <.
1.MD.4. Organize, represent, and interpret data with up to three categories; ask and answer questions about the total number of data points, how many in each category, and how many more or less are in one category than in another.
2.NBT.4. Compare two three-digit numbers based on meanings of the hundreds, tens, and ones digits, using >, =, and < symbols to record the results of comparisons.
**NCTM Standards:** K–3 Expectations

The Number and Operations NCTM Standard states that in prekindergarten through grade 2 all students should develop fluency with basic number combinations for addition and subtraction and use a variety of methods and tools to compute, including estimation. Children should also be able to formulate questions that can be addressed with data and collect, organize, and display relevant data to answer them.

**Teacher notes**:

Estimation is key in this story about saving tips to purchase a chair; the number of variables is small, but the resulting savings can vary widely:

Tips depend on the number of people served in a day and the amount they tip. Fewer people served and low tips will result in little money saved. Many people who tip generously result in large additions to savings. Estimating how many days it will take to save a certain amount of money can provide several lessons in both computation and estimation. It also provides a valuable lesson in data collection.

**Lesson Plan for grade levels K-2**

**New words**: data; estimate; predict; certainty; probably (A simple vocabulary can be used: eliminate the word data and just use coins and tips; instead of predict just ask children to estimate the time it will take; etc.)

**You will need**: A copy of the book; a chalk board or other large board or tablet; coins or chits to represent tips; jar for coins or chits.

**Plan**:

**Anticipatory Set and Objective**: Tell children you will read them a story about a family who is saving to buy a chair. Talk about the concept of saving for something. Ask if it’s often difficult to know when you will have enough saved and why it isn’t always certain.

**Input**: Read the story. Ask children what the family was going to save. Talk about tips and tipping in a restaurant. Bring out the coins or chits and the jar and talk about adding coins to the jar. How many would you add in a day? Would it always be the same number?

**Modeling:** This could be done over a period of several lessons.

Set up a restaurant atmosphere with as little or as much equipment as time allows. This can be as simple as grouping children at tables. Have one student act the part of the server. Give each of the groups a certain amount of coins or chits. Have the groups of children tip the server, with each group deciding independently on the amount to give. Put the tips in the jar and count the coins. Begin to accumulate a total. Write the total on the board.

**Guided practice**:

After the first “day”, decide how many days it would take to arrive at the needed amount if every day were the same as this day. Do this by adding the total over and over until you reach the set amount. Write the number of days next to the total.

Change the numbers in each group of ‘diners’ and the number of groups at the tables, increasing or decreasing the number of groups served, and then repeat the tipping. Count all the tips. Is it more or less than the last? Use the symbols <, >, and = as you write the numbers and record the amount. Decide how many days it would take to arrive at the needed amount if every day were the same as this day.

Add the chits to the jar and add the first and second days together. Write the total on the board. Depending on whether there were more or less tips, will it take more or less time to reach the goal? Discuss the outcome, leading to the realization that the time needed to reach the goal will vary, but can be predicted.

**Checking Understanding**: Ask the children to repeat the days with less and less guidance until the goal is reached. On the “day” they reach the goal, they will ‘probably’ have a bit more money than needed. Discuss this.

**Independent practice**: Ask the children to write about one thing they would like to save to buy. Have them state the cost, what money they will save and how long it might take to save enough. In this assignment you could repeat the word probably and help the children further understand its meaning.