Rian— ...........
W h a t is th e fir s t s tep
in fin d in g each sum?
Identify whether the
addends have the
same sign or different
signs. Then choose the
appropriate rule to use.
The absolute value o f a n u m b e r is it s d is ta n c e f r o m 0 o n a n u m b e r l in e. A b s o lu t e v a lu e
is a lw a ys n o n n e g a tiv e sin c e d is ta n c e is a lw a y s n o n n e g a tiv e.
F o r e x a m p le , th e a b s o lu te v a lu e o f 4 is 4 a n d th e a b s o lu te v a lu e o f - 4 is 4. Y o u c a n w r it e
th is as^14 j = 4 a n d | — 4^1 = 4.
4 units 4 units
H ►+* H
-*-♦ 1 1 1 1 1 1 1 ♦—- 4 - 3 - 2 - 1 0 1 2 3 4
Y o u c a n u s e a b s o lu te v a lu e w h e n y o u f i n d t h e s u m s o f r e a l n u m b e r s.K e y C o n c e p t A dding Real NumbersAAdding Numbers W ith the Same Sign
T o a d d t w o n u m b e r s w i t h t h e s a m e s ig n , a d d t h e i r a b s o lu te v a lu e s. T h e s u m h a s the
same sign as the addends.
Examples 3 + 4 = 7 - 3 + (-4 ) =-7Adding Numbers W ith Different Signs
T o a d d t w o n u m b e r s w i t h d if f e r e n t s ig n s , s u b t r a c t t h e i r a b s o lu te v a lu e s. T h e s u m h a s
the sam e sign as th e a d d e n d w ith th e greater absolute value.
Examples -3 + 4 = 1 3 + (—4) = —1
^ ........... JiAdding Real Numbers
What is each sum?0-12 + 7
The difference o f the absolute values is 5. The negative addend has the greater- 1 2 + 7 = —5 absolute value. The sum is negative.
0 -18 + (-2)-1 8 + (-2 )0 - 4 .8 + 9 .5+ r 21 _ _ 2 q The addends have the same sign (negative), so add their absolute
values. The sum is negative.- 4 8 + 9 5 = 4 7 T^ e d 'fference absolute values is 4.7. The positive addend has the
greater absolute value. The sum is positive.
o! + (-§)
| + | - |j = 12 + ( ~ J§) 'east common denominator.
1_ The difference o f the absolute values is The negative addend
12 has the greater absolute value. The sum is negative.G ot It? 2. W h a t is e a c h s u m?
a. - 1 6 + ( - 8 ) b. -1 1 + 9 c. 9 + (—11) d. -6 + (-2 )