Money Amounts with a Calculator - Everyday Math

Money Amounts with a Calculator

Objectives To guide children as they enter money amounts

into a calculator and interpret calculator displays.



ePresentations

eToolkit

Algorithms Practice

EM Facts Workshop GameTM

Family Letters

Assessment Management

Common Core State Standards

Curriculum Focal Points

Interactive Teacher's Lesson Guide

Teaching the Lesson

Ongoing Learning & Practice

Differentiation Options

Key Concepts and Skills ? Count by 1s, 5s, 10s, 25s, and 100s.

[Number and Numeration Goal 1]

? Read and write money amounts in dollars-and-cents notation. [Number and Numeration Goal 2]

? Calculate the value of coin and bill combinations. [Operations and Computation Goal 2]

? Find equivalent names for money amounts. [Measurement and Reference Frames Goal 4]

Key Activities Children enter money amounts in dollarsand-cents notation into their calculators and interpret calculator displays. Children practice entering money amounts and finding totals on the calculator by playing Pick-a-Coin.

Ongoing Assessment: Informing Instruction See page 741.

Materials Math Journal 2, pp. 234?237 Home Link 10 2 Math Masters, p. 469 (optional) transparency of Math Masters, p. 469 (optional) slate calculator per group: 1 die; coins and bills (optional) overhead calculator (optional)

Using Square Units to Find Area Math Journal 2, p. 238 My Reference Book, p. 69B straightedge or ruler (optional) Children use square units to practice finding the area of different shapes.

Math Boxes 10 3 Math Journal 2, p. 239 Children practice and maintain skills through Math Box problems.

Ongoing Assessment: Recognizing Student Achievement Use Math Boxes, Problem 2.

[Number and Numeration Goal 3]

Home Link 10 3 Math Masters, p. 300 Children practice and maintain skills through Home Link activities.

READINESS

Doing Money Calculator Counts Math Masters, p. 301 My Reference Book, pp. 162 and 163 calculator tool-kit coins Children interpret calculator decimal notation displays as money amounts in dollar-and-cents notation.

ENRICHMENT

Displaying Money on the Calculator Math Masters, p. 302 Children translate calculator decimal notation displays into dollar-and-cents notation.

Advance Preparation

You may want to use an overhead calculator for demonstration purposes throughout this lesson. You may want to take 2 days to complete this lesson.

For the Pick-a-Coin game in Part 1, you may want to make copies of Math Masters, page 469 for children to use as additional record tables. You may also want to make an overhead transparency of that page.

For a mathematics and literacy connection, obtain a copy of How the Second Grade Got $8,205.50 to Visit the Statue of Liberty by Nathan Zimelman (Albert Whitman, 1992).

Lesson 10 3 737

Getting Started

Mental Math and Reflexes

Dictate amounts like the following. Children write them in dollars-and-cents notation on their slates.

2 dollars and 71 cents $2.71 45 cents $0.45 9 cents $0.09

Math Message

Enter these numbers into your calculator. Write what you see in the display on your slates.

Number

Display

1.02

1.02

.98

0.98

.980

0.98

1.02 - .980 =

0.04

Be prepared to share what you notice about the displays.

Home Link 10 2 Follow-Up

Review answers. Have children share strategies for both of the practice problems.

On Day 1 of this lesson, complete the Math Message Follow-Up; Entering Amounts Greater than and Less than $1.00 into a calculator; and Examining Variations Displayed on Calculators.

On Day 2 of this lesson, introduce Pick-a-Coin and the Part 2 activities.

Student Page

Date

LESSON

10 3

Time

Calculator Dollars and Cents

To enter $4.27 into your calculator, press 4 . 2 7 .

To enter 35? into your calculator, press . 3 5 . 1. Enter $3.58 into your calculator. The display shows

3.58 .

2. Enter the following amounts into your calculator.

Record what the display shows. Don't forget to clear between each entry.

Price

Display

$2.75 $1.69

2.75 1.69

$12.32

12.32

Make up prices that are more than $1.00.

Answers vary.

Answers vary.

Answers vary.

3. Enter 68? into your calculator. The display shows

Math Journal 2, p. 234

229_262_EMCS_S_SMJ_G2_U10_57640X.indd 234

0.68 .

3/3/11 7:37 AM

738 Unit 10 Decimals and Place Value

1 Teaching the Lesson

Math Message Follow-Up

WHOLE-CLASS DISCUSSION

Children briefly discuss what they notice about the displays. If no one suggests it, point out that a 0 appears before the .98 and before the difference 0.04. Children may also notice that the trailing zeros disappear. Ask: Can you enter 2.2.2? No Explain that this is not a number the calculator is programmed to understand.

Entering Amounts Greater than $1.00 into a Calculator

(Math Journal 2, p. 234)

WHOLE-CLASS ACTIVITY

Ask children to describe how they would enter $3.58 into a calculator. Press 3 . 5 8 . Point out that because the calculator does not have a key for the dollar sign, you enter the amount without a dollar sign.

Problems 1 and 2 on journal page 234 provide practice with entering amounts more than $1.00. Work with children on these problems; provide additional practice if needed.

Entering Amounts Less than $1.00 into a Calculator

(Math Journal 2, pp. 234 and 235)

WHOLE-CLASS ACTIVITY

Ask children to do Problem 3 on journal page 234. Ask:

How did you enter 68 cents into the calculator? Press . 6 8 . On most calculators, the display shows 0.68.

What does the zero in front of the decimal point tell you? The amount is less than 1 dollar.

NOTE Some children might comment that pressing 0

.

before

6

8

does not affect the number in the display.

Examining Variations in

WHOLE-CLASS ACTIVITY

Decimals Displayed on Calculators

(Math Journal 2, pp. 234 and 235)

At times, a calculator displays numbers that do not look exactly like what children might write on their papers. It is a good idea to point out such differences in order to avoid confusion.

Have children add 65 cents and 35 cents on their calculators, using dollars-and-cents notation. The display shows "1." with a decimal point. This stands for $1.00. Since there are no cents in the sum, the calculator automatically omits the zeros after the decimal point.

Ask children to add 30 cents and 20 cents on their calculators, using dollars-and-cents notation. The display shows "0.5"--the zero after the 5 in "0.50" is omitted. The calculator display stands for $0.50; one can also think of $0.50 as 5 dimes.

Have children do Problem 5 on journal page 235.

Playing Pick-a-Coin

(Math Journal 2, pp. 236 and 237; Math Masters, p. 469)

SMALL-GROUP ACTIVITY

PROBLEM SOLVING

In Pick-a-Coin, players create coin collections based on rolls of a die. Players try to get the largest possible values for their collections. Demonstrate several turns as needed.

1. Draw a Pick-a-Coin record table on the board or display an overhead transparency of Math Masters, page 469.

Student Page

Date

Time

LESSON

10 3

Calculator Dollars and Cents continued

4. Enter the following amounts into your calculator. Record what you see in the display.

Price

Display

$0.10 $0.26

0.10 0.26

$0.09

0.09

Make up prices that are less than $1.00.

Answers vary.

Answers vary.

Answers vary.

5. Use your calculator to add $1.55 and $0.25.

What does the display show? 1.8

Explain what happened.

Sample answer: Because

$1.55 + $0.25 = $1.80, the calculator doesn't show a zero for

the cents. It shows the number of dollars and dimes only.

Math Journal 2, p. 235

229_262_EMCS_S_SMJ_G2_U10_57640X.indd 235

3/3/11 7:37 AM

NOTE A few calculators do not add a trailing decimal point. Also, if a calculator has a "fix" key to fix the number of decimal places shown in the display for any number, there could be trailing zeros.

Student Page

Date

Time

LESSON

10 3

Pick-a-Coin Directions

Materials 1 die calculator for each player

Pick-a-Coin record table for each player (Math Journal 2, p. 237 or Math Masters, p. 469)

Players

2 to 4

Skill

Add dollar bill and coin combinations

Object of the Game To add the largest value

Summary Players roll a die. The numbers that come up are used as numbers of coins and dollar bills. Players try to make collections of coins and bills with the largest value.

Directions Take turns. When it is your turn, roll the die five times. After each roll, record the number that comes up on the die in any one of the empty cells in the row for that turn on your record table. Then use a calculator to find the total amount for that turn. Record the total in the table.

After four turns, use your calculator to add the four totals. The player with the largest Grand Total wins.

Example: On his first turn, Brian rolled 4, 2, 4, 1, and 6. He filled in his record table like this:

Pick-a-Coin Record Table

?

?

?

?

Total

1st turn

2 1 4

4

6 $ 7 . 47

2nd turn

$ .

3rd turn

$ .

4th turn

$ .

Grand Total $ .

Math Journal 2, p. 236

229_262_EMCS_S_SMJ_G2_U10_57640X.indd 236

3/3/11 7:37 AM

Lesson 10 3 739

Student Page

Date

LESSON

10 3

Time

Pick-a-Coin Record Tables

?

?

?

?

Total

1st turn 2nd turn 3rd turn

$ . $ . $ .

4th turn

Answers vary.

$ . Grand Total $ .

?

?

?

?

Total

1st turn 2nd turn 3rd turn 4th turn

$ . $ . $ . $ .

Grand Total $ .

?

?

?

?

1st turn

2nd turn

3rd turn

4th turn

Grand Total

Math Journal 2, p. 237

229_262_EMCS_S_SMJ_G2_U10_57640X.indd 237

Total

$ . $ . $ . $ . $ .

3/3/11 7:37 AM

2. Roll a die to demonstrate one turn. Write the number that comes up in one of the empty boxes in the "1st turn" row. The number represents that number of pennies, nickels, dimes, quarters, or $1 bills. Roll the die 4 more times to complete the turn. Write the numbers in the same row. Example:

? ? ? ? Total

1st turn

1

3

2

2

5

$

.

2nd turn

$

.

3rd turn

$

.

4th turn

$

.

Grand Total (total for all 4 turns)

$

.

Say that once a number has been written in a box, it cannot be erased and moved somewhere else.

Adjusting the Activity

ELL

Provide coins and bills for children to use during the game. Have children write the total amount for each coin in the box. For example: 1 ? = 1?; 3 ? = 15?; 2 ? = 20?, and so on.

AUDITORY

KINESTHETIC

TACTILE

VISUAL

Student Page

Date

Time

LESSON

10 3

Finding Area

Find the area of the shapes below. For Problem 1, count the square centimeters to find the area. For Problems 2?4, draw lines to show the square units. Use the tick marks as a guide. Then count the squares to find the area.

1.

2.

2 in.

2 in.

Area = 3.

32 sq cm

6 cm

Area = 4

4.

5 cm

sq in.

2 cm

3 cm

4 cm

3 cm

2 cm

Area = 18 sq cm

Try This

5. Draw tick marks and line segments to make square units. Then count the squares to find the area.

3 cm

2 cm

Area = 14 sq cm

5 cm

Math Journal 2, p. 238

229_262_EMCS_S_SMJ_G2_U10_57640X.indd 238

Area = 15 sq cm

3/18/11 2:06 PM

740 Unit 10 Decimals and Place Value

3. Show how to use a calculator to find the total amount for that turn. For example:

1 penny + 3 nickels + 2 dimes + 2 quarters + 5 dollars

0.01 + 0.05 + 0.05 + 0.05 + 0.1 + 0.1 + 0.25 + 0.25 + 5 = 5.86 or 0.01 + 0.15 + 0.2 + 0.5 + 5 = 5.86

4. Point out that the winner is the player who gets the largest possible Grand Total (the total for all four turns), so it is important to try to get the largest possible total on each turn.

When most children understand what to do, divide the class into groups of 2, 3, or 4. Then lead children through the steps for the first turn. They can complete the next 3 turns on their own.

There are three record tables on journal page 237. If children continue to play, they can use copies of Math Masters, page 469 or draw their own record tables.

Ongoing Assessment: Informing Instruction

Watch for children who are having difficulty entering amounts less than $0.10 on the calculator. Remind children that the first digit after the decimal point represents dimes. The second digit after the decimal point represents pennies.

2 Ongoing Learning & Practice

Using Square Units to Find Area

(Math Journal 2, p. 238; My Reference Book, p. 69B)

INDEPENDENT ACTIVITY

Have children complete journal page 238 independently. For Problem 1, children count the square units to find the area. For Problems 2?4, they draw lines to make square units and then count the squares to find the area. When drawing the lines, it is not necessary for children to use a ruler or straightedge.

Math Boxes 10 3

(Math Journal 2, p. 239)

INDEPENDENT ACTIVITY

Mixed Practice Math Boxes in this lesson are linked with Math Boxes in Lessons 10-1 and 10-5. The skill in Problem 6 previews Unit 11 content.

Writing/Reasoning Have children draw, write, or verbalize their answers to the following: Explain why the number of nickels in $3.00 is double the number of dimes in $3.00. Sample answer: A nickel is worth 5 cents and a dime is worth 10 cents. 5 is half of 10.

Ongoing Assessment:

Math Boxes

Recognizing Student Achievement Problem 2

Use Math Boxes, Problem 2 to assess children's ability to model fractions as

equal parts of a collection. Children are making adequate progress if they can

find

_ 1 2

of

the

20

pennies

with

or

without

counters

or

pennies.

Some

children

may

be

able

to

find

_ 1 4

and

_15 .

[Number and Numeration Goal 3]

Home Link 10 3

(Math Masters, p. 300)

INDEPENDENT ACTIVITY

Home Connection Children complete a table showing the total value of a coin collection. Children also ask someone at home to help them collect pennies, nickels, dimes, quarters, and half-dollars (if available). They find the total value of each kind of coin and the total value of all the coins in the collection.

Student Page

Date

Time

LESSON

10 3

Math Boxes

1. 300 pennies = $3.00 60 nickels = $3.00 30 dimes = $3.00 12 quarters = $3.00

2. Count 20 pennies.

_ 1

2

=

10

pennies

_ 1

4

=

5

pennies

_ 1

5

=

4

pennies

3. Complete the frames. 1,000 100

2,463 3,463 3,363

5,263 4,263 4,363

5. Match.

5 ft

3 yd

24 in.

60 in.

9 ft

2 ft

4. Solve.

Unit

9-5= 4

40 = 90 - 50

900 - 500 = 400

4,000 = 9,000 - 5,000

6. Draw an 8-by-4 array. How many in all?

67

Math Journal 2, p. 239

229_262_EMCS_S_SMJ_G2_U10_57640X.indd 239

3/3/11 7:37 AM

Adjusting the Activity

Once children have some experience playing the game, discuss strategies with them. Ask where they would write 1 and why. Then ask where they would write 6 and other numbers.

AUDITORY KINESTHETIC TACTILE VISUAL

Home Link Master

Name

Date

Time

HOME LINK

10 3

Coin Values

Family In today's lesson, your child used a calculator to enter amounts of money and find totals. For Note Problem 2, help your child collect and find the total value of each type of coin. Then find the

grand total. If you wish to use a calculator, help your child enter the amounts. Remind your child that amounts like $1.00 and $0.50 will be displayed on the calculator as "1." and "0.5" because the calculator doesn't display ending zeros.

Please return this Home Link to school tomorrow.

1. Complete the table.

Coins Number of Coins

?

6

?

10

?

13

6

Total Value

$ 0 . 06

$ 0 . 50

$ 1 . 30

$ 1 . 50

Grand Total

$ 3 . 36

2. Ask someone at home to help you collect pennies, nickels, dimes, quarters, and, if possible, half-dollars. Use the coins in your collection to complete the table below.

Coins Number of Coins

Total Value

?

?

?

Halfdollar

Practice

Solve.

3. 250 + 53 = 300

Grand Total

Answers vary.

4. 250 - 53 = 197

Math Masters, p. 300

293-347_EMCS_B_MM_G2_U10_576949.indd 300

3/1/11 4:29 PM

Lesson 10 3 741

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