Pre-Algebra 2-2 Subtracting Integers Today’s Learning Goal Assignment Learn to subtract integers.

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

Pre-Algebra 2-2 Subtracting Integers Lesson Quiz: Part 2 Evaluate each expression for the given value of the variable – s for s = –5 5. –4 – w + 5 for w = –20

Pre-Algebra 2-2 Subtracting Integers Are we ready for the FAST TRACK?

Pre-Algebra 2-2 Subtracting Integers Pre-Algebra: 2-2 HW Page 66 #9-23 all

Pre-Algebra 2-2 Subtracting Integers 2-2 Subtracting Integers Pre-Algebra Warm Up Warm Up Problem of the Day Problem of the Day Lesson Presentation Lesson Presentation

Pre-Algebra 2-2 Subtracting Integers Warm Up Add. 1. – –6 + (–28) 2. –12 + (–9) (–87) (–19) 6. –18 + (–24) Pre-Algebra 2-2 Subtracting Integers –5–5–34 17 –42 –21 13

Pre-Algebra 2-2 Subtracting Integers Problem of the Day Copy and complete the magic square. The magic sum is 0. –8–8+3 –2–20 –3–3 +5 –2 –5–5+8

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

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) = a – b = a + (–b) a – (–b) = a + b

Pre-Algebra 2-2 Subtracting Integers Additional Example 1: Subtracting Integers A. –7 – 4 –7 – 4 = –7 + (–4) B. 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.

Pre-Algebra 2-2 Subtracting Integers Try This: Example 1 A. 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.

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. = = 14 Add the opposite of –6. Same sign; use the sign of the integers. Additional Example 2A: Evaluating Expressions with Integers

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. Additional Example 2B: Evaluating Expressions with Integers

Pre-Algebra 2-2 Subtracting Integers C. n – 6 for n = –2 n – 6n – 6 –2 – 6Substitute –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. Additional Example 2C: Evaluating Expressions with Integers

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. = = 14 Add the opposite of –3. Same sign; use the sign of the integers. Try This: Example 2A

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

Pre-Algebra 2-2 Subtracting Integers C. a – 7 for a = –9 a – 7 –9 – 7Substitute –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

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? Additional Example 3: Architecture Application 1454 – (–43) Subtract the lowest level from the height 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.

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 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.