(1)
1621=(42)21=4
(2)
(259)21=(5232)21=53
(3)
6−2=361
(4)
(54)2=2516
(5)
80=1
(6)
2.4×103=2.4×1000=2400
(7)
25−21=(52)−21=51
(8)
62543=(54)43=53=125
(9)
16−43=(24)−43=2−3=81
(10)
1221⋅323=(34⋅22)21=32⋅2=18
(11)
33324=38=323=2
(12)
5−32=5(−2)5=−2