Mastering Addition and Subtraction of Rational Numbers with Number Lines
210 likes | 239 Vues
Learn how to add and subtract real numbers using a number line. Understand the rules for moving left or right and changing directions for negative numbers. Practice various addition and subtraction exercises to improve your skills.
Mastering Addition and Subtraction of Rational Numbers with Number Lines
E N D
Presentation Transcript
The set of all numbers that can be represented on a number line are called real numbers. You can use a number line to help you with addition and subtraction of real numbers. Addition To add a number, always move to the right. Subtraction To subtract a number, always move to the left. BUT: If adding or subtracting a NEGATIVE number, switch directions.
-3 -1 0 1 2 3 4 6 8 9 -2 7 5 Add or subtract using a number line. –3 + 7 Start at 0. Move left to –3. To add 7, move right 7 units. +7 –3 –3 + 7 = 4
11 10 7 6 5 4 3 2 1 9 8 0 Add or subtract using a number line. –4 + (–7) Start at 0. Move left to –4. To add –7, move left 7 units. + (–7) –4 –4 + (–7) = –11
-3 -2 -1 0 1 2 3 4 5 6 8 9 7 Add or subtract using a number line. 3 – (–6) Start at 0. Move right to 3. To subtract –6, move right6units. –(–6) + 3 3 – (–6) = 9
Add or subtract using a number line. –3 – 7 Start at 0. Move left to –3. To subtract 7, move left 7 units. –7 –3 11 10 6 9 8 7 5 4 3 2 1 0 –3 – 7 = –10
Subtracting can be thought of as the “opposite of”. 5 – (–4) 5 − (–4) = 5 + 4 To subtract –4, add 4. 5 − 4 = 5 + 4 (– ) (5 + 4 = 9) = 9
Add or subtract using a number line. –5 – (–6.5) Start at 0. Move left to –5. To subtract –6.5, move right 6.5 units. – (–6.5) –5 8 7 6 5 2 1 0 1 2 4 3 –5 – (–6.5) = 1.5
Another way to look at it: a) b) c) d) e) 7 + 12 So, try some now: 1) 2) 3) 4) –2 – 9 –13 – 4 6 – (–8) 10 – (-9) –5 + 8 –11 + 6 5 - 14 2 +(-13)
Chapter 2.3 and 2.4 – Multiplying and Dividing Rational Numbers When you multiply or divide two numbers, the signs of the numbers determine whether the result is positive or negative. Numbers Product/Quotient Both positive Positive Negative One negative Both negative Positive
Find the value of each expression. A. C. –5 B. 12
Simplify each expression a.) 4(-3y) – 15y b.) 13x + (-6)(4x) -12y – 15y -27y 13x + (-24x) -11x
The value of a company’s stock dropped by $1.25 per share. By what amount did the total value of the company’s stock change if the company has issued 500,000 shares of the stock? Stock Market Example 500,000 (1.25) = $625,000 DROP!!
Two numbers are reciprocals if their product is 1. A number and its reciprocal are called multiplicativeinverses. To divide by a number, you can multiply by its multiplicative inverse.
Evaluate the expression. Example 2 Dividing by Fractions
Helpful Hint You can write the reciprocal of a number by switching the numerator and denominator. A number written without a denominator has a denominator of 1.
Simplify each expression a.) b.) 3a + 2 – 12x + 8
Lesson Review Simplify. a. -8 + 13 e. b. 7 – 19 f. c. -12 – (-15) g. h. d. -10 + (-36)
Assignment • 2-2, 2-3 & 2-4 Study Guide/Skills Practice Worksheets (In-Class) Homework • Pages 823 – Lesson 2-2 Odds • Pages 823 – Lesson 2-3 Odds • Pages 824 – Lesson 2-4 Odds • Quiz on Sections 1-1, 1-2, 1-5, 2-2, 2-3, and 2-4 on Friday, September 18th!!!