Opposite Quantities Combine to
Make Zero
Lesson 1
Do Now
Write one sentence for each of the following:
1) What I know about integers:
2) What I would like to know about integers:
Today we will…
Identify and graph integers on a number line
and
Add positive integers by counting up and
negative integers by counting down by using
arrows on the number line
Math Magic
• Step 1: Think of any number.
Step 2: Multiply the number you have thought
with 3.
Step 3: Add 45 with the result.
Step 4: Double the result.
Step 5: Divide the answer by 6.
Step 6: Subtract the answer from the number you
have thought.
• Is your number 15?
Vocabulary
• Integer:
• Positive integer:
• Negative integer:
• Number line:
Positive and Negative Numbers
Review
With your partner, use the graphic organizer below to record what you know
about positive and negative numbers.
Positive Numbers
Negative Numbers
Word Problems
Circle which integer is represented by the word following word problems.
1) James walked 4 feet towards the destination.
a) +4
b) -4
c) +8
d) -8
2) Steph took out $50 from the bank.
a) +50
b) -50
c) +100
d) -100
3) John ate 4 of his Halloween candies.
a) +4
b) -4
c) +8
d) -2
4) Susie lost 5 pounds on her diet.
a) +15
b) -10
c) +5
d) -5
5) Yesterday it was 20 degrees below zero.
a) +20
b) -20
c) +40
d) -40
Your turn!
• Positive and negative integers can be represented
many ways. For example: temperature, money, etc.
Step 1: Individually, create one word problem to
represent a positive integer and one to represent a
negative integer.
Step 2: Share with your partner and state the integer
represented.
Counting Up and Counting Down on
the Number Line
• Counting up corresponds to _____________ numbers
• Counting down corresponds to ____________ numbers.
New Definition: Absolute Value
a) Where do you begin when locating a number on the number
line?
Start at 0.
a) What do you call the distance between a
number and 0 on a number line?
The absolute value
What is the relationship between 7 and −7?
7 and -7 both have the same absolute values. They are both the same distance
from zero, just in opposite directions.
Additive Inverse
Definition: What you add to a number to get zero.
Example:
The additive inverse of -5 is 5, because -5 + 5 = 0.
The additive inverse of +5 is -5 as well.
Practice
Find the additive inverse of each of the
following:
1) 6
2) -18
3) -1
4) 50
HOW TO PLAY THE INTEGER GAME
Each player begins the game with a score of zero. The
object of the game is to return to a score of zero.
Rules:
• Pick a dealer to provide each player with 4 cards.
• The dealer turns one more card face up on the table,
starting a discard pile. The remaining cards become a
draw pile.
Rules
• When it is your turn, select the top card from either
the draw pile or the discard pile. If you want to keep
this card, discard another card from your hand.
• The goal is to have your hand’s total card value stay
as close to zero as possible. So for each turn, decide
how the card drawn affects your hand, by counting
up or down.
Rules
• Play continues until all players have picked up
and discarded a card four times.
• The player with a score of zero or closest to
zero wins the round!
The Integer Game
• What is the final position on the number line?
• What card or combination of cards would you need to
get back to 0?
LET’S PLAY!
EXIT TICKET: A look back to the Do
Now
Write second sentence for each of the following:
1) What I know about integers:
2) What I would like to know about integers: