## Chapter 22

### Part 1: For the problem in the Teacher's Edition, page 584

Students can practice their research skills by finding elevations of different places in the world, or you can provide them with the data sheet with information about Elevations of Places in the World found in the Activity Page (PDF file).

#### Data Sheet

After the students have found four places that they want to work with, ask them to write the elevations in order from greatest to least. Remind them that elevations below sea level are negative numbers and thus are less than zero.

Ask the students how they would find the difference between an above-sea-level elevation and a below-sea-level elevation. Bring out in the discussion that you would actually add the number of feet above sea level and the number of feet below sea level to find the difference. You might want to discuss an example with them. Death Valley is 282 feet below sea level, and Mount McKinley is 20,320 feet above sea level. The difference between these two elevations is 282 feet + 20,320 feet, or 20,602 feet.

Answers will vary.

### Part 2: Be an Investigator

A good time to do this investigation is after Lesson 5 on adding and subtracting integers.

#### Introducing the Investigation

Introduce the investigation by reading aloud the assignment at the top of the first page of the Description of Investigation and Student Report (PDF file), by having one of your students read aloud the assignment, or by having the students read the assignment individually.

Put the students in groups of two to four to work on the investigation.

#### Doing the Investigation

The first part of Joe's account statement is filled out for the students. You might want to do a few more lines of his account together as a class to help the students get started. Make sure the students understand that a negative number in the account means the account is overdrawn.

#### Data Sheet

#### Answers for Data Sheet:

Action in Account | Number Sentence to Calculate Money in Account | Money in Account |
---|---|---|

$6 | ||

Deposit $4 | 6 + 4 = 10 | $10 |

Withdraw $5 | 10 − 5 = 5 | $5 |

Withdraw $6 | 5 − 6 = −1 | −$1 |

Deposit $3 | −1 + 3 = 2 | $2 |

Action in Account | Number Sentence to Calculate Money in Account | Money in Account |
---|---|---|

$12 | ||

Withdraw $13 | 12 − 13 = −1 | −$1 |

Withdraw $7 | −1 + −7 = −8 | −$8 |

Deposit $5 | −8 + 5 = −3 | −$3 |

Action in Account | Number Sentence to Calculate Money in Account | Money in Account |
---|---|---|

$6 | ||

Deposit $10 | 6 + 10 = 16 | $16 |

Withdraw $18 | 16 − 18 = −2 | −$2 |

Deposit $8 | −2 + 8 = 6 | $6 |

#### Student Report

The student report gives the students an opportunity to show what they have done.

#### Extending the Investigation

Have the students start a recording system for their own money that they keep in a bank or a piggy bank.