Evaluating Algebraic Expressions 1-4Adding Integers Warm Up Warm Up California Standards California Standards Lesson Presentation Lesson PresentationPreview

Evaluating Algebraic Expressions 1-4Adding Integers Warm Up Graph each number on a number line. 1. – –44. 0 –5 –4 –3 –2 –

Evaluating Algebraic Expressions 1-4Adding Integers NS1.2 Add, subtract, multiply, and divide rational numbers (integers, fractions, and terminating decimals) and take positive rational numbers to whole-number powers. AF1.3 Simplify numerical expressions by applying properties of rational numbers (e.g. identity, inverse, distributive, associative, commutative) and justify the process used. California Standards

Evaluating Algebraic Expressions 1-4Adding Integers Vocabulary additive inverse

Evaluating Algebraic Expressions 1-4Adding Integers To add a positive number move to the right. To add a negative number move to the left. Helpful Hint Additional Example 1A: Using a Number Line to Add Integers Use a number line to find the sum. (–6) –6 You finish at –4, so (–6) + 2 = –4. –6 –5 –4 –3 –2 – Start at 0. Move left 6 units. From –6, move right 2 units.

Evaluating Algebraic Expressions 1-4Adding Integers Additional Example 1B: Using a Number Line to Add Integers Use a number line to find the sum. –3 + (–6) –3–6 You finish at –9, so –3 + (–6) = –9. –9 –8 –7 –6 –5 –4 –3 –2 – Start at 0. Move left 3 units. From –3, move left 6 units.

Evaluating Algebraic Expressions 1-4Adding Integers Check It Out! Example 1A Use a number line to find the sum. (–3) –3 You finish at 4, so (–3) + 7 = 4. –6 –5 –4 –3 –2 – Start at 0. Move left 3 units. From –3, move right 7 units.

Evaluating Algebraic Expressions 1-4Adding Integers Check It Out! Example 1B Use a number line to find the sum. (–2) –2 You finish at 2, so (–2) + 4 = 2. –6 –5 –4 –3 –2 – Start at 0. Move left 2 units. From –2, move right 4 units.

Evaluating Algebraic Expressions 1-4Adding Integers Another way to add integers is to use absolute value.

Evaluating Algebraic Expressions 1-4Adding Integers Additional Example 2: Using Absolute Value to Add Integers A. 1 + (–2) Add. 1 + (–2) 2 > 1; use the sign of 2. –1 B. (–8) + 5 (–8) > 5; use the sign of 8. –3 Think: Find the difference of 1 and –2. Think: Find the difference of –8 and 5.

Evaluating Algebraic Expressions 1-4Adding Integers Additional Example 2: Using Absolute Value to Add Integers C. (–2) + (–4) Add. (–2) + (–4) Same sign; use the sign of the integers. –6 Think: Find the sum of –2 and –4.

Evaluating Algebraic Expressions 1-4Adding Integers Check It Out! Example 2 A. 3 + (–6) Add. 3 + (–6) 6 > 3; use the sign of 6. –3 B. (–4) + 1 (–4) > 1; use the sign of 4. –3 Think: Find the difference of 3 and –6. Think: Find the difference of –4 and 1.

Evaluating Algebraic Expressions 1-4Adding Integers Check It Out! Example 2 C. (–6) + (–7) Add. (–6) + (–7) Same sign; use the sign of the integers. –13 Think: Find the sum of –6 and –7.

Evaluating Algebraic Expressions 1-4Adding Integers Additional Example 3: Evaluating Expressions with Integers Evaluate c + 4 for c = –8. c + 4 Replace c with –8. 8 > 4; use the sign of 8. (–8) + 4 –8 + 4 = –4 Think: Find the difference of –8 and 4.

Evaluating Algebraic Expressions 1-4Adding Integers Check It Out! Example 3 Evaluate d + 7 for d = –3. d + 7 Replace d with –3. 7 > 3; use the sign of 7. (–3) + 7 –3 + 7 = 4 Think: Find the difference of –3 and 7.

Evaluating Algebraic Expressions 1-4Adding Integers Additional Example 4: Application Meka opened a new bank account. Find her account balance after the first four transactions listed below. Deposits: $200, $20 Withdrawals: $166, $38 Use a positive sign for deposits and a negative sign for withdrawals (–166) + (–38) Group integers with the same signs. ( ) + (–166 + –38) Add integers within each group (–204) 220 > 204; use the sign of Meka’s account balance after the first four transactions is $16.

Evaluating Algebraic Expressions 1-4Adding Integers Check It Out! Example 4 Michael opened a new bank account. Find his account balance after the first four transactions listed below. Deposits: $175, $95 Withdrawals: $133, $65 Use a positive sign for deposits and a negative sign for withdrawals (–133) + (–65) Group integers with the same signs. ( ) + (–133 + –65) Add integers within each group (–198) 270 > 198; use the sign of Michael’s account balance after the first four transactions is $72.

Evaluating Algebraic Expressions 1-4Adding Integers Lesson Quiz Add. 1. –7 + (–7) (–9) + (–2) 4–14 Evaluate each expression for the given value of the variable r for r = – b + (–9) for b = –6 –2–13 5. On Monday, a local dog shelter had six dogs. By Friday, they had found homes for three, but took in two more. Then how many dogs were in the shelter? 5 dogs