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How do you subtract integers?

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Presentation on theme: "How do you subtract integers?"— Presentation transcript:

1 How do you subtract integers?
1.3 Subtracting integers How do you subtract integers?

2 Subtracting Integers Rewrite the problem to ADD THE OPPOSITE
Follow the addition rules Same Sign Keep the same sign Different Sign Take the sign of the value with higher absolute value Order Matters – Greater to lesser

3 Modeling Modeling integer subtraction p. 19-20
Subtracting on a Number line p

4 Practice Your turn p. 22 #4-7 1.3 Worksheet
Independent Practice #16-21 Guided Practice #1-14

5 1.4 Applying Addition and Subtraction of Integers
How do you solve multistep problems involving addition and subtraction of integers?

6 Example 1: A seal is swimming in the ocean 5 feet below sea level
Example 1: A seal is swimming in the ocean 5 feet below sea level. It dives down 12 feet to catch some fish. Then, the seal swims 8 feet up towards the surface with its catch. What is the seal’s final elevation relative to sea level? Step 1 Write an expression. The seal starts at 5 feet below the surface, so its initial position is -5ft Start - dives down + swims up Step 2 Add or subtract from left to right to find the value of the expression. -5 – = = - 9 The seal’s final elevation is 9 feet below sea level.

7 Try it Anna is in a cave 40 feet below the cave entrance. She descends 13 feet, then ascends 18 feet. Find her new position relative to the cave entrance. -40 – ; -35 35 feet below the cave entrance

8 Example 2: Irene has a checking account
Example 2: Irene has a checking account. Monday she writes a $160 check for groceries. Then she deposits $125. Finally she writes another check for $40. What was the total change in the amount in Irene’s account? Step 1 Analyze the information Decide which numbers were positive and which numbers should be negative. - $160, $125, -$40 Step 2 Solve (-40) = = -75 The amount in the account decreased $75

9 Try it Alex wrote checks on Tuesday for $35 and $45. He also made a deposit in his checking account of $180. Find the overall change in the amount in his checking account. -35 + (-45) + 180 = = 100 $100 increase

10 Try it The Tigers, a football team, must gain 10 yards in the next four plays to keep possession of the ball. The Tigers lose 12 yards, gain 5 yards, lose 8 yards, and gain 14 yards. Do the Tigers maintain possession of the ball? (-8) + 14 = = - 1 yard The Tigers do not maintain possession of the ball.

11 Try it Jim and Carla are scuba diving. Jim started out 10 feet below the surface. He descended 18 feet, rose 5 feet, and descended 12 more feet. Then he rested. Carla started out at the surface. She descended 20 feet, rose 5 feet and descended another 18 feet. Then she rested. Which person rested at a greater depth? Explain Jim: (-18) (-12) = -35 feet at resting Carla: (-18) = - 33 feet at resting

12 Let’s Practice Page 28 # 1-11 Page 29-30 # 13 – 20
Adding and Subtracting Word Problems Worksheet Module 1B Quiz 1.4 Quiz


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