1. Pre-Algebra 2-2 Subtracting Integers Learn to subtract integers.

2. Pre-Algebra 2-2 Subtracting 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 WordsNumbersAlgebra Change the subtraction sign to an addition sign and change the sign of the second number. 2 – 3 = 2 + (–3) 4 – (–5) = 4 + 5 a – b = a + (– b ) a – (– b) = a + b

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

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

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

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

7. Pre-Algebra 2-2 Subtracting 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 WordsNumbersAlgebra Change the subtraction sign to an addition sign and change the sign of the second number. 2 – 3 = 2 + (–3) 4 – (–5) = 4 + 5 a – b = a + (– b ) a – (– b) = a + b

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

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

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

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

12. Pre-Algebra 2-2 Subtracting Integers 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? Example 3: Architecture Application 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.

13. Pre-Algebra 2-2 Subtracting Integers 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? Try This: Example 3 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.