Resposta:
a) +10 + 2 = +12
B)+2+21 = +23
C)+5+18 = +23
D)+23+21 = +44
E)+12+34 = +46
F)+12-8 = +4
G)+15-6 = +9
H)+45-32 = +13
i) +56-34 = +22
J)+57-31 = +26
K)-32+25 = -7
L)-23+12 = -11
M)-15+13 = -2
N)-45+40 = -5
O)-35+27 = -8
P)-23+32 = +9
Q)-32+53 = +21
R)-12+32 = +20
Espero ter ajudado :)