Integers

What is an integer? An integer is any number from the set { . . . -3, -2, -1, 0, +1, +2, +3, . . . } where . . . means without end. negative integers positive integers -9 -8 -7 -6 -5 -4 -3 -2 -1 0 +1 +2 +3 +4 +5 +6 +7 +8 +9 Negative numbers are written with a - sign. Positive numbers are written with or without a + sign.

Numbers to the left of zero on the number line are negative integers. Numbers to the right of zero on the number line are positive integers. Zero is not positive or negative. negative integers positive integers -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9

Give the opposite of each situation. Up 7 floors Down 7 floors North 15 miles South 15 miles Lose 7 points Gain 7 points Right 3 blocks Left 3 blocks Spent $12 Earned $12 2° below zero 2° above zero 20 feet above sea level 20 feet below sea level

Each integer has an opposite Each integer has an opposite. Opposite integers are the same distance from zero on opposite sides of the number line. Zero is considered to be the starting point. -7 +7 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 +1 +2 +3 +4 +5 +6 +7 +8 +9

Give the opposite of each integer. -4 ____ 4 42 ____ -42 -7 ____ +7 -68 ____ 68 +12 ____ -12 25 ____ -25 37 ____ -37 -72 ____ 72 negative integers positive integers -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9

Integers can be used to describe real life situations. What integer would show? The stock market up by 27 points +27 The stock market down by 15 points -15 A gain of 7 pounds +7 A loss of 3 club members -3 An increase of 17° in temperature 17 A gain of 5 yards on a football play 5 A loss of 12 yards on a football play -12 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9

Erin got on an elevator and went up 9 floors Erin got on an elevator and went up 9 floors. Express this number as an integer. +9 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9

David lost 11 pounds. Express this number as an integer. -11 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9

Kevin received a $200 bonus. Express this number as an integer. +$200 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9

A scuba diver is 25 feet below sea level A scuba diver is 25 feet below sea level. Express this number as an integer. -25 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9

The value of a stock decreased by $17 The value of a stock decreased by $17. Express this number as an integer. -17 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9

Which situation is represented by the integer +4? 4 degrees above normal 4 degrees below normal a discount of $4 a loss of 4 pounds

Which situation is represented by the integer -8? moving forward 8 feet 8 feet above sea level a decrease of $8 a rise of 8°

Which situation is represented by the integer -12? 12 feet above sea level a deposit of $12 a price increase of $12 going down 12 floors

Which situation is represented by the integer +35? a loss of $35 a deposit of $35 a $35 deduction going down 35 feet

A football player caught the ball and started running straight toward the goal line. He gained 15 yards. Then, a player from the other team pushed him back 5 yards. The football player was able to gain 4 more yards, but he lost 5 yards again when he was tackled. Write the expression that shows how many yards the football player gained before being tackled. 15 - 5 + 4 - 5

During January, the low temperature for a Tuesday morning was -4° During January, the low temperature for a Tuesday morning was -4°. The temperature rose 15° during the day. Then it fell 10° on Tuesday night. Write the expression to find the low temperature on Tuesday night. -4 + 15 - 10

Gregory gave an oral report for history class Gregory gave an oral report for history class. He received 40 points for creating a colorful poster as a visual aid. He lost 10 points because he forgot to turn in his written report in advance. He earned 50 points because all of the historical facts he used were accurate. He also earned 5 extra-credit points for good presentation skills. Write the expression that shows how many points he earned for his oral report. 40 - 10 + 50 + 5

Mark and his brother went to the park Mark and his brother went to the park. Mark had 3 quarters in his pocket. He also found a nickel and a dime on the sidewalk where they were walking. Mark gave his brother 50 cents to pay for a snow cone. Write the expression that shows how many cents Mark had left. 75 + 5 + 10 - 50