199又199分之198乘以-5 简便算法咋算.急

问题描述:

199又199分之198乘以-5 简便算法咋算.急

(199 +198/199) x (-5) = (200-1+1-1/199) x(-5) =(200-1/199) x(-5) =-1000+5/199 =-999又194/199