Download Adding Real Numbers We can add numbers using a number line

Adding Real Numbers
We can add numbers using a number line.
Example: -3+6
Start by putting a point on -3, and since 6 is positive we will move 6
places to the right to get the answer. So -3+6=3
Example: -4+(-5)
Start by putting a point on -4, and since -5 is negative we will move 5
places to the left to get the answer. So -4+(-5)=-9
Rules of addition:

To add 2 numbers with the same sign, add their absolute values. The sum has
the same sign as the numbers added.
o 8+7=15
o -6+(-10)=-16

To add 2 numbers with different signs, subtract the lesser absolute value
from the greater absolute value. The sum has the same sign as the number
with the greater absolute value.
o -12+7=-5
o 18+(-4)=14
Properties of addition

Commutative Property
o The order in which you add 2 numbers does not change the sum.
o a+b=b+a

Associative Property
o The way you group 3 numbers in a sum does not change the sum.
o (a+b)+c=a+(b+c)

Identity Property
o The sum of a number and 0 is the number.
o a+0=0+a=a

Inverse Property
o The sum of a number and its opposite is 0.
o a+(-a)=-a+a=0