a) 16/9-4/3+1 amplificãm pe 4/3 cu 3 si pe 1 cu 9
(16-12+9)/9=13/9
b) [4+9/4]:25/4 amplificãm pe 4 cu 4
[16/4+9/4]:25/4=25/4×4/25=1
c) 81/16:(3/2) la puterea 3-1/2=81/16:27/8-1/2=81/16×8/27-1/2=3/2-1/2=2/2=1
d) (3/5) la puterea 21:(3/5) la puterea 20+2/5=3/5+2/5=5/5=1