1. 1-4 Adding Real Numbers Hubarth Algebra

2. Identity Property of Addition For every real number n, n+0 = n and 0+n = n. Ex.-5 + 0 = -50 + 5 = 5 The opposite of a number is its additive inverse. Ex.The additive inverse of 10 is -10 The additive inverse of -25 is 25 Inverse Property of Addition For every real number n, there is a additive inverse –n such that n + (-n) = 0 Ex.14 + (-14) = 0-14 + 14 = 0

3. a. 3 + (–5) 3 + (–5) = –2 b. –3 + 5 –3 + 5 = 2 Start at –3. Move left 5 units. Start at –3. Move right 5 units. c. –3 + (–5) –3 + (–5) = –8 Start at –3. Move left 5 units. Ex. 1 Using a Number Line Model Simplify each expression

4. Rules Adding Numbers With the Same Signs To add two number with the same sign, add the absolute values of the two numbers together and keep the sign the same for your answer. Ex.5 + 16 = 21-8 + (-15) = -23 Adding Numbers With Different Signs To add two numbers with different signs, subtract the absolute value of the smaller value from the larger and take the sign of the larger number for your answer. Ex.-6 + 8 = 212 + (-15) = -3

5. Simplify each expression. a. 12 + (–23) = b. –6.4 + (–8.6) = Ex 2 Adding Numbers c. 5.6 + 3.4 = d. -34 + 38 = -11 -15 9 4

6. The water level in a lake rose 6 inches and then fell 11 inches. Write an addition statement to find the total change in water level. 6 + (–11) = –5 The water level fell 5 inches. Ex 3 Application

7. Evaluate 3.6 + (–t) for t = –3. 3.6 + (–t) = 3.6 + [–(–3)]Substitute –3 for t. = 3.6 + [3]–(–3) means the opposite of –3, which is 3. = 6.6Simplify. Ex 4 Evaluating Expressions

8. Practice 1.Simplify each expression a.3 + (-5) = b. -3 + 5 =c. -12 + -23 = d. -6.4 + 8.6 = 2. A football team gains 2 yards and then loses 7 yards in two plays. Use addition to find the result of the two plays. 3. Evaluate n + 8.9 for n = -3 -2 2-35 2.2 2 + (-7) = -5 (-3) + 8.9 -3 + 8.9 5.9