Answer:
Step-by-step explanation:
im pretty sure its just simple addition and subtraction,
rise= add
"1c, RISE of 3c"
1 + 3= 4c
fall= subtract
"-2c, FALL of 6c"
-2 - 6= -8c
i hope that helps :D
(if its wrong correct me)
Refer to the attachment please! :)
