## Summary

## Objectives

Using coins as the standard of measure, students will estimate and check weights of classroom objects.

## Subject Area

- Math

## Grades

- K
- 1st

## Class Time

- Total Time: 0-45 minutes

## Materials

- Cents
- Quarters
- Balance scales (one per group)
- "Tip the Scales" work pages (pages 24 and 25)
- Pencils
- Crayons

## Lesson Steps

- Explain that the class will work in groups to estimate the weights of classroom objects, and then check their estimates at weighing stations. Review the terms "estimate," "weight," and "balance."
- Display the "Tip the Scales" work pages (pages 24 and 25). Explain that everyone in the group will work together to weigh the objects and check the estimates.
- Sit at one of the work stations and explain that you will demonstrate the entire estimation/weighing process with a different item than the ones the children will work with.
- Hold up an eraser and ask a volunteer to estimate how many cents will weigh the same as the eraser. Write the estimate in the spaces provided on the work page.
- Place the eraser on the scale and ask students to remind you how many cents have been estimated to balance the scale. Start putting cents in the scale and count aloud.
- Add cents until the scale is balanced or the estimated number has been reached. (It may be necessary to explain what the scale should look like when it is balanced.)
- If the estimated number comes first, then discuss what happened, and whether or not the estimate has been confirmed. Then, add cents until the scale is balanced. If the scale balances before the estimated number has been reached, discuss how close the estimate was to the actual number of cents needed.
- Remind students that they will be weighing different classroom objects, and show them the objects they will work with.
- Assign groups and send each group to a station. You may wish to assign jobs (balancer, counter, cent dropper) within each group, so that every child participates. Students could then rotate jobs with each new object.
- Allow students 25 minutes to complete the tasks. When time is called, ask students to share how close their estimates were, and what surprised them during the activity. You may wish to discuss the "brain teaser" activity on the work page, highlighting the difference between weight and value (25 cents are worth one quarter, but 25 cents weigh more than one quarter).

## Assess

Use the worksheet and class participation to assess whether the students have met the lesson objectives.

## Common Core Standards

**Discipline**: Math

**Domain**: K.MD Measurement and Data

**Grade(s)**: Grade K

**Cluster**: Describe and compare measurable attributes

**Standards**:

**K.MD.1.**Describe measurable attributes of objects, such as length or weight.- Describe several measurable attributes of a single object

**Discipline**: Math

**Domain**: K.MD Measurement and Data

**Grade(s)**: Grade K

**Cluster**: Describe several measurable attributes of a single object

**Standards**:

**K.MD.2.**Directly compare two objects with a measurable attribute in common, to see which object has "more of"/"less of" the attribute, and describe the difference. For example, directly compare the heights of two children and describe one child as taller/shorter.**K.MD.3.**Classify objects into given categories; count the numbers of objects in each category and sort the categories by count.

## National Standards

**Discipline**: Mathematics

**Domain**: All Problem Solving

**Cluster**: Instructional programs from kindergarten through grade 12 should enable all students to

**Grade(s)**: Grades K–12

**Standards**:

- Build new mathematical knowledge through problem solving
- Solve problems that arise in mathematics and in other contexts
- Apply and adapt a variety of appropriate strategies to solve problems
- Monitor and reflect on the process of mathematical problem solving

**Discipline**: Mathematics

**Domain**: K-2 Data Analysis and Probability

**Cluster**: Develop and evaluate inferences and predictions that are based on data.

**Grade(s)**: Grades K–12

**Standards**:

In K through grade 2 all students should

- discuss events related to students' experiences as likely or unlikely.

**Discipline**: Mathematics

**Domain**: K-2 Data Analysis and Probability

**Cluster**: Formulate questions that can be addressed with data and collect, organize, and display relevant data to answer them.

**Grade(s)**: Grades K–12

**Standards**:

In K through grade 2 all students should

- pose questions and gather data about themselves and their surroundings;
- sort and classify objects according to their attributes and organize data about the objects; and
- represent data using concrete objects, pictures, and graphs.

**Discipline**: Mathematics

**Domain**: K-2 Measurement

**Cluster**: Apply appropriate techniques, tools, and formulas to determine measurements.

**Grade(s)**: Grades K–12

**Standards**:

In K through grade 2 all students should

- measure with multiple copies of units of the same size, such as paper clips laid end to end;
- use repetition of a single unit to measure something larger than the unit, for instance, measuring the length of a room with a single meterstick;
- use tools to measure; and
- develop common referents for measures to make comparisons and estimates.

**Discipline**: Mathematics

**Domain**: K-2 Measurement

**Cluster**: Understand measurable attributes of objects and the units, systems, and processes of measurement.

**Grade(s)**: Grades K–12

**Standards**:

In K through grade 2 all students should

- recognize the attributes of length, volume, weight, area, and time;
- compare and order objects according to these attributes;
- understand how to measure using nonstandard and standard units; and
- select an appropriate unit and tool for the attribute being measured.

**Discipline**: Mathematics

**Domain**: K-2 Number and Operations

**Cluster**: Compute fluently and make reasonable estimates.

**Grade(s)**: Grades K–12

**Standards**:

In K through grade 2 all students should

- develop and use strategies for whole-number computations, with a focus on addition and subtraction;
- develop fluency with basic number combinations for addition and subtraction; and
- use a variety of methods and tools to compute, including objects, mental computation, estimation, paper and pencil, and calculators.