Download 1 - Humble ISD

1.2 – Adding and Subtracting Real Numbers
Negative side
Origin
Positive side
__l_____l_____l_____l_____l_____l_____l_____l____l
-4
-3
-2
-1
0
1
2
3
4
Real numbers – any number that is either positive, negative
or zero; all numbers on the number line
Absolute value – the distance a number is from zero on the
number line
Opposites – two numbers whose sum is zero
Additive inverses – a number and its opposite
Addition and Subtraction Rules
1) Eliminate double signs
a) If the are the same, add
Ex: 5 – (-7)
5 + 7 = 12
b) If they are different, subtract
Ex: 5 + (-7)
5–7=-2
2) If the numbers have the same sign, add and keep the sign
Ex: 5 + 7 = 12
-5 – 7 = -12
3) If the numbers have different, subtract and keep the
sign of the number with the greater absolute value
Ex: 7 – 5 = 2
5–7=-2