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Adding Integers. 2-2. Adding Integers. Course 2. Learn to add integers. 2-2. Adding Integers. Course 2. Review Find each absolute value. 1. |8| 2. | –6 | 3. | – 9| 4. | – 7| 5. | – 12| 6. |53|. 8. 6. 9. 7. 12. 53. 2-2. Adding Integers.
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2-2 Adding Integers Course 2 Learn to add integers.
2-2 Adding Integers Course 2 Review Find each absolute value. 1.|8| 2. |–6| 3. |–9| 4. |–7| 5. |–12| 6. |53| 8 6 9 7 12 53
2-2 Adding Integers –12 –10 –8 –6 –4 –2 0 2 4 6 8 Course 2 Review From Yesterday Use a number line to find each sum. –12 + 19 19 –12 Start at 0. Move left 12 spaces. Then move right 19 spaces. –12 + 19 = 7
Adding Integers = 2 Key Model 5 + (-3) = -1 1. Draw counters to show your first integer = 1 2. Draw counters to show your second integer right next to the first counters 3. One positive cancels a negative, so cross out one for one. What is left is your answer. There are two positives left, so the answer is 2.
Let’s Try some (-5) Key Model 3 + (-8)= Model (-2) + (-4)= = -1 = 1 (-6) There are no positives to cancel out the negatives, so we total up our negatives.
2-2 Adding Integers Course 2 To add two integers with the same sign, find the sum of their absolute values. Use the sign of the two integers. To add two integers with different signs, find the difference of their absolute values. Use the sign of the integer with the greater absolute value.
2-2 Adding Integers Course 2 Additional Example 2A: Adding Integers Using Absolute Values Find each sum. –4 + 8 The signs are different. Find the difference of the absolute values. –4 + 8 Think: 8 – 4 = 4. Use the sign of the integer with the greater absolute value. 4
2-2 Adding Integers Course 2 Additional Example 2B: Adding Integers Using Absolute Values Find each sum. 23 + (–35) The signs are different. Find the difference of the absolute values. 23 + (–35) Think: 35 – 23 = 12. Use the sign of the integer with the greater absolute value. –12
2-2 Adding Integers Course 2 Insert Lesson Title Here Check It Out: Example 2A Find each sum. –5 + 3 The signs are different. Find the difference of the absolute values. –5 + 3 Think: 5 – 3 = 2. Use the sign of the integer with the greater absolute value. –2
2-2 Adding Integers Course 2 Insert Lesson Title Here Check It Out: Example 2B Find each sum. –13 + (–24) The signs are the same. Find the sum of the absolute values. –13 + (–24) Think: 13 + 24 = 37. –37 Use the sign of the two integers.
2-2 Adding Integers Helpful Hint When adding integers, think: if the signs are the same, find the sum. If the signs are different, find the difference. Course 2 Additional Example 3: Evaluating Expressions with Integers Evaluate x + y for x = –42, y = 71. x + y Substitute for x and y. The signs are different. Think 71- 42 = 29 –42 + 71 Use the sign of the integer with the greater absolute value (positive). 29
2-2 Adding Integers Course 2 Insert Lesson Title Here Check It Out: Example 3 Evaluate x + y for x = –24, y = 17. x + y Substitute for x and y. The signs are different. Think: 24 – 17 = 7. –24 + 17 –7 Use the sign of the integer with the greater absolute value (negative).
2-2 Adding Integers Course 2 Additional Example 4: Application The jazz band’s income from a bake sale was $286. Expenses were $21. Use integer addition to find the band’s total profit or loss. 286 + (–21) Use negative for the expenses. Find the differences of the absolute values. 286 – 21 265 The answer is positive. The band earned $265.
2-2 Adding Integers Course 2 Insert Lesson Title Here Check it Out: Example 4 The French Club was raising money for a trip to Washington D.C. Their car wash raised $730. They had expenses of $52. Use integer addition to find the club’s total profit or loss. 730 + (–52) Use negative for the expenses. Find the differences of the absolute values. 730 – 52 678 The answer is positive. The club earned $678.
2-2 Adding Integers –14 –12 –10 –8 –6 –4 –2 0 2 Course 2 Insert Lesson Title Here Lesson Quiz: Part I Use a number line to find the sum. 1. –7 + (–6) Find each sum. 2. –15 + 24 + (–9) 3. –24 + 7 + (–3) 4. Evaluate x + y for x = –2 and y = –15. –13 0 –20 –17
2-2 Adding Integers Course 2 Insert Lesson Title Here Lesson Quiz: Part II 5. The math club’s income from a bake sale was $217. Advertising expenses were $32. Use integer addition to find the club’s total profit or loss? $185 profit