Accentuate the NegativeInvestigation 1

Extending the Number System

PositiveNegative

Positive and Negative

Numbers are called Integers!

1.1 Playing Math FeverUsing Positive and Negative Numbers

If you have a current Math Fever

score of -500 points and then answer the next

four questions like shown above….

You can figure out the Final Score of -600 points!

-600 -550 -500 -450 -400

Start

-500 – 100 = -600Incorrect 100

Correct 200 -600 + 200 = -400

Incorrect 150 -400 - 150 = -550

Incorrect 50 -550 - 50 = -600

End

1.2 From Sauna to SnowbankComparing & Ordering Positive and Negative Numbers

A thermometer is a vertical number line.

Positive

Negative

Order these temperatures from greatest to least:

- 40 1/4° 81.5° 5° -10°

81.5°

5°

-10°

- 40.25°

Opposites are the same distance from Zero:

20° and -20 ° are opposites!

1.3 What’s the Change?Using a Number Line Model

If the temperature rose from -4° F to 45° F in two minutes, what is the change in temperature?

Starting Temp. + Change in Temp. = Ending Temp.

45°4°

Temp. rose = positive number

-4° + n = 45°

-4° + +49° = +45°

1.3 Continued

If the temperature is - 4° F and it drops 10°, what is the ending temperature?

Starting Temp. + Change in Temp. = Ending Temp.

Temp. drops = negative number

- 4° + -10 = n

- 4° + -10 = -14°

1.4 In the ChipsUsing a Chip Model

To solve a problem using a chip board:

• Display 1st # of number sentence onto chip board.• Add or remove chips to represent 2nd # of number sentence. (if chips need to be removed from the board but their aren’t enough

there, chips must be added in the form of zero pairs)• Remove the zero pairs from chip board.• The chips remaining on the board represent the answer.

Negative

Positive

1 Red Chip + 1 Black Chip = a “Zero Pair”

1.4 Practice

1

2

3

4

Display 1st # of number sentence onto chip board.

Add chips to represent 2nd # of number sentence.

Remove the zero pairs from chip board.

The chips remaining on theboard represent the answer.

Remove chips to represent 2nd # of number sentence. Only 2 chips are there, so 1 zero pair must be added.

1.4 Practice

Then, the 3 red can be subtracted.Display 1st # of number sentence onto chip board.

Since there are no zero pairs,two is the answer.

1

2a

2b

3