7乘以15分之8减去7乘以35分之12加7乘以63分之16减99分之20乘以7用简便方法计算

Question

如题所述

Answer 1

解：原式=7*8/15-7*12/35+7*16/63-20/99*7
=7*(8/15-12/35+16/63-20/99)
=7*(1/3+1/5-1/5-1/7+1/7+1/9-1/9-1/11)
=7*(1/3-1/11)
=7*(11/33-3/33)
=7*8/33
=56/33

Answer 2

4528