What: adding and subtracting integers Why: To review and apply the rules for adding and subtracting integers.

Today’s Lesson:

SAME SIGNS

ADD

_____________

3 + 7 = 10-3 + -7 = ?

DIFFERENT SIGNS

_______________

Keep Sign of Larger Absolute

Value

-4 + 2 = -24 + -2 = ?

ADDING INTEGERS:

Keep Sign

SUBTRACT

Video

Evaluate the following examples (ask yourself whether the signs are “same” or “different” ):-28 + -5 = -105 + 4 = -17+ -4 =

50 + 45 = -90 + 11 = 225 + -5 =

examples:

-33 -101 -21

-7995 220

SUBTRACTING INTEGERS:DID YOU KNOW? ALL Subtraction problems are ____________________ problems in disguise! WHY? Because we can re-write every subtraction problem as an addition problem.

KEEP, CHANGE,CHANGE!

addition

Change these into addition problems: -3 – (-7) and -4 – 2

8 – 12 =8 + (- 12) = -4

5 – (-1) =5 + 1 = 6

Re-write the following subtraction problems as addition problems (KCC): DO NOT SOLVE!5 – 8 -12 – 6 -14 – (-7)

32 – 4 -88 – (-11) 8 – 10

Let’s practice our “KCC”:

5 + (-8) -12 + (-6) -14 + 7

8 + (-10)-88 + 1132 + (-4)

Evaluate the following examples (Use KCC first):25 – 32 = -12 – (-4) = -11 – 7 =

62 – 4 = -80 – 11 = 8 – (-15) =

Now, let’s solve!:

-7 -8 -18

23-9158

1. A Navy submarine was 50 ft. below sea level. It rose 15 ft., sank 90 ft., rose 20 ft., and sank 15 ft. Where is the submarine?

Word problems:

-120 ft. below sea-level.

Word problems:

2. An airplane was at an elevation of 400 ft. above the ground. It descended 125 ft., and descended an additional 75 ft. However, it was in the flight path of another plane, so it ascended 100 ft. What is the plane’s altitude? 300 ft. above the ground.

Word problems:

3. It was a brisk 10°F on a wintery night in Alaska. However, the wind-chill factor made it feel like it was -8°F. What is the difference between these two temperatures? The difference is 18⁰ .

Word problems:

4. The record low temperature for January in Augusta, Maine is -15°F, while the record high temperature is 45°F. What is the difference between the record low and the record high?

The difference is 60⁰ .

Word problems:

5. The temperature on Monday was 12°F. By Tuesday, it fell 20 degrees. What was the temperature on Tuesday?-8⁰F

Word problems:

6. In four consecutive plays, the Steelers gained 10 yards, lost 5 yards, gained 15 yards, and lost 10 yards. What was their final yardage ? They gained 10 yards (+10) .

Word problems:

7. Write a story problem about temperature, money, or game scores to represent the following number sentence: 7 – (-5) = 12

END OF LESSON

The next slides are student copies of the notes for this lesson. These notes were handed out in class

and filled-in as the lesson progressed.

NOTE: The last slide(s) in any lesson slideshow (entitled “Practice Work”)

represent the homework assigned for that day.

ADDING INTEGERS (Review):

Math-7 NOTES DATE: ______/_______/_______What: adding and subtracting integers Why: To review the rules for adding and subtracting integers.

NAME:

SAME SIGNS

ADD

_____________

3 + 7 = 10-3 + -7 = ___

DIFFERENT SIGNS

_______________

Keep Sign of Larger

Absolute Value

-4 + 2 = -2 4 + -2 = ___

Evaluate the following examples (ask yourself whether the signs are “same” or “different” ):-28 + -5 = -105 + 4 = -17+ -4 =

50 + 45 = -90 + 11 = 225 + -5 =

examples:

Change these into addition problems: -3 – (-7) and -4 – 2

Evaluate the following examples (Use KCC first):25 – 32 = -12 – (-4) = -11 – 7 =

62 – 4 = -80 – 11 = 8 – (-15) =

Re-write the following subtraction problems as addition problems (KCC):DO NOT SOLVE!5 – 8 -12 – 6 -14 – (-7)32 – 4 -88 – (-11) 8 – 10

SUBTRACTING INTEGERS:DID YOU KNOW? ALL Subtraction problems are ____________________ problems in disguise! WHY?Because we can re-write every subtraction problem asan addition problem.

KEEP, CHANGE,CHANGE!

8 – 12 =8 + (- 12) = -4

5 – (-1) =5 + 1 = 6

Integer word problems:1. A Navy submarine was 50 ft. below sea level. It rose 15 ft., sank 90 ft., rose 20 ft., and sank 15 ft. Where is the submarine?2. An airplane was at an elevation of 400 ft. above the ground. It descended 125 ft., and descended an additional 75 ft. However, it was in the flight path of another plane, so it ascended 100 ft. What is the plane’s altitude?

3. It was a brisk 10°F on a wintery night in Alaska. However, the wind-chill factor made it feel like it was -8°F. What is the difference between these two temperatures?

4. The record low temperature for January in Augusta, Maine is -15°F, while the record high temperature is 45°F. What is the difference between the record low and the record high?

5. The temperature on Monday was 12°F. By Tuesday, it fell 20 degrees. What was the temperature on Tuesday?6. In four different plays, the Steelers gained 10 yards, lost 5 yards, gained 15 yards, and lost 10 yards. What was their final yardage ?

7. Write a story problem about temperature, money, or game scores to represent the following number sentence: 7 – (-5) = 12

Adding Integers:

Subtracting Integers (re-write as addition problems first– KCC):

“Add and subtract integers”PRACTICE WORK

NAME:________________________________________________________________________________DATE: _____/_____/__________

Answer the following problems (SHOW WORK). 1. Steve is balancing his checkbook for the week. He began the week $15.00 in debt (- $15.00). However, he received two paychecks– one for $128.00 and another for $32.00. He also received two bills– one for $84.00 and another for $66.00. After depositing the checks and paying the bills, how much did Steve end up with? 2. Claire entered the elevator on the 8th Floor. She rode the elevator down nine levels, up six levels, and down four more levels. What floor did she end up on? 3. Some divers were 25 ft. below sea level. They ascended 12 ft., descended 32 ft., and ascended 40 feet. Where are the divers now? 4. It was 10°F on Saturday, but the temperature fell 18° by Sunday. What was the temperature on Sunday?5. On a snowy day in Maine, the temperature was 14°F, but the wind-chill factor made it feel like it was -4°F. What is the difference between the real temperature and the wind-chill factor? 6. Write a story problem that represents the following integer problem:

Your problem could be about sports, money, temp., orsomething else of your choosing.

-5 – 15 + 30 = _____

“Integer word problems”PRACTICE WORK

NAME:________________________________________________________________________________DATE: _____/_____/__________