The Addition and Subtraction of Negative Numbers

1. The Addition and Subtraction of Negative Numbers (-4)+2=(-2) 2+(-7)=(-5) (-6)+7=1 0+(-9)=(-9) 9+(-11)=(-2) 5+(-8)=(-3) 8+(-13)=(-5) (-7)+(-9)=(-16) 2+(-5)=(-3) (-3)+7=4 (-5)+9=4 Created by Danicia Braun

2. Negative and Positive Numbers • The set of negative and positive numbers is called the set of integers. • Integers = {….,-4, -3, -2,-1,0,1,2,3,4,….} “dots mean it keeps going” • Also a number line can be used to show the set of negative and positive numbers. “arrows mean it keeps going”

3. Same Sign: If the two number that are being added together have the same sign, just find the sum and use that sign. Ex. 4 + 5 = 9 or (-7) + (-4) = (-11) * Always use the sign of the number that has the greater absolute value. In subtraction or addition. Different Signs: If the two number have different signs. First throw the signs away and take the difference of the two numbers. Then take the sign of the number with the greater absolute value. Ex. (-3) + 5 = ? 5 – 3 = 2 |5|=5 and |-3| = 3 Because 5 is greater then 3 you will use 5’s sign. (-3) + 5 = 2 Addition

4. Subtraction • First change the subtraction problem into a addition problem. • Then follow the addition rules. Ex. (-4) – 8 = ? So change to an addition problem. First number stays the same (-4) Next change the operation (-4) + Change the sign of the second number (-4) + (-8) = Then add the two numbers together (-4) + (-8) = 12 Other examples: 1. 6 – (-7) = First change to addition and then add. 6 + (+7) = 13 2. (-5) – (-4) = First change to addition then add. (-5) + (+4) = (-1)

5. Helpful Links • This site is a very good site that you should take a look at. Addition and Subtraction of Integers • This is a great site to go to, to get some help on integers. Integers

6. Test Yourself • Test what you have learned with this worksheet below and then check your answers with the answer sheet. • Worksheet • Answers to Worksheet