Question

9/5×25%+5/1×4/1-0.2怎样简便运算？

Answer 1

9/5×25%+5/1×4/1-0.2
=1.8 x 0.25 +20 -0.2
=2x0.9x0.25 +20-0.2
=0.9x0.5 +20-0.2
=0.45 +20-0.2
=20.25

Answer 2

5/9×25%+1/5×1/4-0.2
=5/9×1/4+1/5×1/4-1/5
=(5/9+1/5)×1/4-1/5
=34/45×1/4-1/5
=17/90-1/5
=-1/90