11. What is the sum if you add (-6) and (+9)?
a. -8
b. 3
c. - 17
d. 0
12. -9 added to -9
a.-9
b. 18
c. O
d.-18
13. The sum of (+12) and (-4).
a.-16
b. 16
C. 8
d. -8
14. Which of these statements is true?
a. (-5)+ 9 = 6
c.-25 + 27 = -3
b. 6 + (-16) = -10
d.-96+ (-12) = -84
15. What is the sum of -18 and +18?
a.
b. 1
C.-36
d. +36​