简便运算:7.7*15分之8-7*35分之12+7*63分之16-99分之20*7 怎么简便运算!

7.7*15分之8-7*35分之12+7*63分之16-99分之20*7
= 7.7*8/15-7*12/35+7*16/63-20/99*7
=77*8/150-12/5+16/9-140/99
=(75+2)*4/75-2- 2/5+1+7/9-1 -41/99
=4-2+1-1 +2*4/75- 2/5+7/9 -41/99
=2 - (50-8)/75 + (77-41)/99
=2 - 42/75 + 36/99
=2 - 42/75 + 4/11
=1708/825
=2.0703