Exercicios resoltos:
a) 15-(10+2)=15-12=3
b) 20-(12+8)=20-20=0
f) 5-(-2) + (-8)-(-4)-5=5+2-8+4-5=11-13= -2
g) 7. (-3) – (-8): (-8).2 -3:(-1)= -21-1.2 +3 =-21-2+3= -23 +3= -20