2-2 Adding Integers Course 2 Warm Up Warm Up Problem of the Day Problem of the Day Lesson Presentation Lesson Presentation

Warm Up Find each absolute value. 1. |8| 2. |–6| 3. |–9| 4. |–7| 5. |–12| 6. |53| Course Adding Integers

Problem of the Day Jan’s yearly salary is $30,000, and it will be increased by $3,000 each year. Phil’s salary is $20,000, and it will be increased by $5,000 each year. In how many years will Jan and Phil both have the same yearly salary? 5 years Course Adding Integers

Learn to add integers. Course Adding Integers

Use a number line to find each sum. Additional Example 1A: Modeling Integer Addition Course Adding Integers 2 –14 –12 –10 –8 –6 –4 –2 0 –7 + (–4) –7 +(–4) –7 + (–4) = –11 Start at 0. Move left 7 spaces. Then move left 4 more spaces.

Use a number line to find each sum. Additional Example 1B: Modeling Integer Addition Course Adding Integers – –12 19 – = 7 Start at 0. Move left 12 spaces. Then move right 19 spaces –12 –10 –8 –6 –4 –2 0

Check It Out: Example 1A Insert Lesson Title Here Course Adding Integers Use a number line to find each sum. 2 –14 –12 –10 –8 –6 –4 –2 0 –4 + (–5) –4 +(–5) –4 + (–5) = –9 Start at 0. Move left 4 spaces. Then move left 5 more spaces.

Check It Out: Example 1B Insert Lesson Title Here Course Adding Integers Use a number line to find each sum. – –7 12 – = 5 Start at 0. Move left 7 spaces. Then move right 12 spaces –12 –10 –8 –6 –4 –2 0

Course Adding Integers 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.

Find each sum. Additional Example 2A: Adding Integers Using Absolute Values Course Adding Integers –4 + 8 The signs are different. Find the difference of the absolute values. Think: 8 – 4 = 4. Use the sign of the integer with the greater absolute value. 4

Additional Example 2B: Adding Integers Using Absolute Values Course Adding Integers Find each sum (–35) The signs are different. Find the difference of the absolute values. Think: 35 – 23 = 12. Use the sign of the integer with the greater absolute value. –12

Check It Out: Example 2A Insert Lesson Title Here Course Adding Integers Find each sum. –5 + 3 Think: 5 – 3 = 2. Use the sign of the integer with the greater absolute value. –2 The signs are different. Find the difference of the absolute values.

Check It Out: Example 2B Insert Lesson Title Here Course Adding Integers Find each sum. –13 + (–24) The signs are the same. Find the sum of the absolute values. Think: = 37. Use the sign of the two integers.–37

Evaluate x + y for x = –42, y = 71. Additional Example 3: Evaluating Expressions with Integers Course Adding Integers x + y – Substitute for x and y. The signs are different. Think = 29 Use the sign of the integer with the greater absolute value (positive). 29 When adding integers, think: if the signs are the same, find the sum. If the signs are different, find the difference. Helpful Hint

Check It Out: Example 3 Insert Lesson Title Here Course Adding Integers Evaluate x + y for x = –24, y = 17. x + y – Substitute for x and y. The signs are different. Think: 24 – 17 = 7. Use the sign of the integer with the greater absolute value (negative). –7

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. Additional Example 4: Application Course Adding Integers (–21) 286 – The band earned $265. Use negative for the expenses. Find the differences of the absolute values. The answer is positive.

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. Insert Lesson Title Here Course Adding Integers (–52) 730 – The club earned $678. Use negative for the expenses. Find the differences of the absolute values. The answer is positive.

Lesson Quiz: Part I Use a number line to find the sum. 1. –7 + (–6) Find each sum. 2. – (–9) 3. – (–3) 4. Evaluate x + y for x = –2 and y = –15. 0 –13 Insert Lesson Title Here –20 –17 Course Adding Integers 2 –14 –12 –10 –8 –6 –4 –2 0

Lesson Quiz: Part II Insert Lesson Title Here Course Adding Integers 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