University:
High School
Course:
High School Mathematics
Academic year:

2023
Views:

71

Pages:

3
Author:

anon

Adding & Subtracting Integers The addition of integers can be shown by moves on a number line. - Start at the first integer - Move to the right for positive integers - Move to the left for negative integers To subtract an integer, add its opposite. Example 1: Evaluate. a) (+3)+(+4)=+7 b) (-3)+(-4)=-7 c) (+3)+(-4)=-1 d) (-3)+(+4)=+1 When evaluating expressions, keep in mind that: If the numbers have the same sign, then add up the numbers and carry the sign. If the numbers have different signs, then • add the integers with the same sign • Find the difference between the two numbers and carry the sign of the number that is the greater distance from zero Evaluate -7 + 2 - 5 + 6 using a Scoreboard approach Place the numbers under the appropriate heading Determine each team‛s final score Which team won? By how much? Hwk.: Pg. 19: #3 a) (-2)(+5)(-7)=[(-2)(+5)](-7) =(-10)(-7) =+70 g) (+5)(-1)(-1)(-1)=-5 #4. c) (-2)(-6)-(+5)(-2)=12-(-10) =22 Pg. 23 #2. d) (-85)/5=-17 #3. c) ((-10)(12))/(5)(-3))=(-120)/(-15) =8 #4. f) (-42)/7-(54)/(-6)=(-6)-(-9) =3 Example 2: Evaluate the following. a) (+1) - (-6) - (+3) - (-4) =+1+6-3+4 ← multiply double signs =+1+6+4-3 ← add numbers with the same signs =11-3 =8 b) (-2)-1(+6)-(-4)-(+7) =2-6+4-7 =-2-6-7+4 =-15+4 =-11 c) 7-2-6+4-8+2 =7+4+2-2-6-8 =13-16 =-3 Example 3: The time difference between Toronto and Vancouver is 3 hours. a)An airplane leaves Vancouver for Toronto at 8:00 and the flying time is 4 hours and 10 minutes. What time does it arrive in Toronto? b)On the return flight the airplane leaves Toronto at 7:30 and the flying time to Vanco uver is 4 h and 50 min. What tie does it arrive in Vancouver? Solution: a) (8:00+3:00)+4:10=11:00+4:10 =15:10 The plabe arrives in Toronto at 15:10 (3:10 p.m) b) (7:30-3:00)+4:50=4:30+4:50 =9:20 The plabe arrives in Vanconver at 9:20