2 2 Subtracting Integers Warm Up Problem of

2 -2 Subtracting Integers Warm Up Problem of the Day Lesson Presentation Course 3

2 -2 Subtracting Integers Warm Up Add. 1. – 7 + 2 – 5 4. – 6 + (– 28) 2. – 12 + (– 9) – 21 5. 104 + (– 87) 3. 32 + (– 19) Course 3 13 6. – 18 + (– 24) – 34 17 – 42

2 -2 Subtracting Integers Problem of the Day Copy and complete the magic square. The magic sum is 0. Course 3 +5 – 8 +3 – 2 0 +2 – 3 +8 – 5

2 -2 Subtracting Integers Learn to subtract integers. Course 3

2 -2 Subtracting Insert Lesson Title Here Integers Subtracting a smaller number from a larger number is the same as finding how far apart the two numbers are on a number line. Subtracting an integer is the same as adding its opposite. SUBTRACTING INTEGERS Words Change the subtraction sign to an addition sign and change the sign of the second number. Course 3 Numbers Algebra 2 – 3 = 2 + (– 3) 4 – (– 5) = 4 + 5 a – b = a + (–b) a – (–b) = a + b

2 -2 Subtracting Integers Additional Example 1: Subtracting Integers Subtract. A. – 7 – 4 = – 7 + (– 4) Add the opposite of 4. = – 11 Same sign; use the sign of the integers. B. 8 – (– 5) = 8 + 5 Add the opposite of – 5. = 13 Same sign; use the sign of the integers. C. – 6 – (– 3) = – 6 + 3 Add the opposite of – 3. = – 3 6 > 3; use the sign of 6. Course 3

2 -2 Subtracting Integers Try This: Example 1 Subtract. A. 3 – (– 6) = 3 + 6 =9 Add the opposite of – 6. Same signs; use the sign of the integers. B. – 4 – 1 = – 4 + (– 1) Add the opposite of 1. = – 5 Same sign; use the sign of the integers. C. – 7 – (– 8) = – 7 + 8 Add the opposite of – 8. =1 8 > 7; use the sign of 8. Course 3

2 -2 Subtracting Integers Additional Example 2 A: Evaluating Expressions with Integers Evaluate the expression for the given value of the variable. A. 8 – j for j = – 6 8–j 8 – (– 6) Substitute – 6 for j. =8+6 Add the opposite of – 6. = 14 Same sign; use the sign of the integers. Course 3

2 -2 Subtracting Integers Additional Example 2 B: Evaluating Expressions with Integers Evaluate the expression for the given value of the variable. B. – 9 – y for y = – 4 – 9 – y – 9 – (– 4) Substitute – 4 for y. = – 9 + 4 Add the opposite of – 4. = – 5 9 > 4; use the sign of 9. Course 3

2 -2 Subtracting Integers Additional Example 2 C: Evaluating Expressions with Integers Evaluate each expression for the given value of the variable. C. n – 6 for n = – 2 n– 6 – 2 – 6 = – 2 + (– 6) = – 8 Course 3 Substitute – 2 for n. Add the opposite of 6. Same sign; use the sign of the integers.

2 -2 Subtracting Integers Try This: Example 2 A Evaluate the expression for the given value of the variable. A. 11 – m for m = – 3 11 – m 11 – (– 3) Substitute – 3 for m. = 11 + 3 Add the opposite of – 3. = 14 Same sign; use the sign of the integers. Course 3

2 -2 Subtracting Integers Try This: Example 2 B Evaluate the expression for the given value of the variable. B. – 5 – r for r = – 2 – 5 – r – 5 – (– 2) Substitute – 2 for r. = – 5 + 2 Add the opposite of – 2. = – 3 5 > 2; use the sign of 5. Course 3

2 -2 Subtracting Integers Try This: Example 2 C Evaluate each expression for the given value of the variable. C. a – 7 for a = – 9 a– 7 – 9 – 7 = – 9 + (– 7) = – 16 Course 3 Substitute – 9 for a. Add the opposite of 7. Same sign; use the sign of the integers.

2 -2 Subtracting Integers Additional Example 3: Architecture Application The top of the Sears Tower in Chicago, is 1454 feet above street level, while the lowest level is 43 feet below street level. How far is it from the lowest level to the top? 1454 – (– 43) Subtract the lowest level from the height. 1454 + 43 Add the opposite of (– 43). = 1497 Same sign; use the sign of the integers. It is 1497 feet from the lowest level to the top. Course 3

2 -2 Subtracting Integers Try This: Example 3 The distance from the high dive to the swimming pool is 10 feet. The pool is 12 feet deep. What is the total distance from the high dive to the bottom of the pool? 10 – (– 12) Subtract the depth of the pool from the height of the high dive. 10 + 12 Add the opposite of (– 12). = 22 Same sign; use the sign of the integers. It is 22 feet from the diving board to the bottom of the pool. Course 3

2 -2 Subtracting Insert Lesson Integers Title Here Lesson Quiz: Part 1 1. Write a subtraction equation for the number line diagram. – 4 – 3 – 2 – 1 2 – 3 – 2 = – 3 0 1 2 Perform the given operations. 2. – 6 – (– 4) – 2 3. – 9 – 4 + (– 3) – 16 Course 3 3 4

2 -2 Subtracting Insert Lesson Integers Title Here Lesson Quiz: Part 2 Evaluate each expression for the given value of the variable. 4. 9 – s for s = – 5 14 5. – 4 – w + 5 for w = 21 – 20 Course 3