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Operations with Integers PowerPoint. Created By: Miss Henry. What is an Integer?. A whole number that is either greater than 0 (positive) or less than 0 (negative) Can be visualized on a number line:. What is a Number Line?.
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Operations with Integers PowerPoint Created By: Miss Henry
What is an Integer? • A whole number that is either greater than 0 (positive) or less than 0 (negative) • Can be visualized on a number line:
What is a Number Line? • A line with arrows on both ends that show the integers with slash marks • Arrows show the line goes to infinity in both directions ( + and -) • Uses a negative sign (-) with negative numbers but no positive sign (+) with positive numbers • Zero is the origin and is neither negative nor positive
What are Opposites? • Two integers the same distance from the origin, but on different sides of zero • Every positive integer has a negative integer an equal distance from the origin • Example: The opposite of 6 is -6 • Example: The opposite of -2 is 2
What is Absolute Value? • Distance a number is from zero on a number line (always a positive number) • Indicated by two vertical lines | | • Every number has an absolute value • Opposites have the same absolute values since they are the same distance from zero • Example: |-8| = 8 and |8| = 8 • Example: |50| = 50 and |-50| = 50
What Can We Do to Integers? • Integers are numbers, so we can add, subtract, multiply, and divide them • Each operation has different rules to follow
Adding Rules – Same Signs • If the integers have the SAMEsigns: ADD the numbers & keep the same sign! • Positive + Positive = Positive Answer • Negative + Negative = Negative Answer • Examples: -3 + (-10) = ? ? = -13 • 6 + (8) = ? ? = 14
Adding (Same Signs) - Examples #1. -3 + (-10) Step 1:13 Add the #s Step 2: -13 Keep same sign (Both #s are negative – Answer is negative!) #2. 6 + (8) Step 1:14 Add the #s Step 2: 14 Keep same sign (Both #s are positive – Answer is positive!)
Adding Rules – Different Signs • If the integers have the DIFFERENT signs: SUBTRACT the numbers & use sign of the BIGGERnumber! • Bigger # is Positive = Positive Answer • Bigger # is Negative = Negative Answer • Examples: -13 + (7) = ? ? = -6 • 23 + (-8) = ? ? = 15
Adding (Different Signs) - Examples #1. -13 + (7) Step 1:6 Subtract the #s Step 2: -6 Use sign of bigger # (Bigger # is negative - Answer is negative!) #2. 23 + (-8) Step 1:15 Subtract the #s Step 2: 15 Use sign of bigger # (Bigger # is positive - Answer is positive!)
Subtracting Rules • Put ( ) around second number & its sign • ChangeSUBTRACTION sign to an ADDITION sign • Change sign of 2nd number to itsopposite • Follow the rules forADDITION: • -SAME signs: Add & keep the same sign -DIFFERENT signs: Subtract & use sign of bigger # • Examples: -5 – -10= ? ? = 5 • 9 - 23 = ? ? = -14
Subtracting - Examples • #1. -5 – -10 #2. 9 - 23 • Step 1:-5 – (-10)Insert ( ) 9 – (23) • Step 2: -5 + (-10) Change – to + 9 + (23) • Step 3: -5 + (10) Change 2nd sign 9 + (-23) • Step 4:5 Follow adding rules -14d
Multiplying Rules • Multiply the numbers like usual • If the integers have the SAMEsigns: ANSWER will be POSITIVE • If the integers have DIFFERENTsigns: ANSWER will be NEGATIVE • Examples: -3 · (-5) = ? ? = 15 • -9 · (-10) = ? ? = 90 • -7 · 7 = ? ? = -49 • 6 · -6 = ? ? = -36
Multiplying - Examples • #1. -3 · (-5) #2.-9 · (-10) • 15 Multiply the numbers 90 • 15Same signs = Positive Answer 90 • #3. -7 · 7 #4.6 · -6 • 49Multiply the numbers 36 • -49 Different signs = Negative Answer-36
Dividing Rules • Divide the numbers like usual • If the integers have the SAMEsigns: ANSWER will be POSITIVE • If the integers have DIFFERENTsigns: ANSWER will be NEGATIVE • Examples: -33 ÷ (-3) = ? ? = 11 • -90 ÷ (-10) = ? ? = 9 • -20 ÷ 2 = ? ? = -10 • 6 ÷ -6 = ? ? = -1
Dividing - Examples • #1. -33 ÷ (-3) #2.-90 ÷ (-10) • 11 Divide the numbers 9 • 11Same signs = Positive Answer 9 • #3. -20 ÷ 2 #4.6 ÷ -6 • 10 Divide the numbers 1 • -10 Different signs = Negative Answer-1
Mixed Practice Solve the following problems: -9 + - 9 -18 7 · -4 -28 -10 - (-19) 9 -35 ÷ -7 5 15 + -25 -10 -23 - 9 -32
Review • Visit the website below for additional information on integers: • http://www.math.com/school/subject1/ lessons/S1U1L10GL.html • Click on the signs below to review the rules for each operation
Review • Visit the website below for additional information on integers: • http://www.math.com/school/subject1/ lessons/S1U1L10GL.html • Click on the signs below to review the rules for each operation