举报
allstars7936
999又7分之6×99又7分之6×9又7分之6再加7分之6 =(1000-1/7)×(100-1/7)×(10-1/7)+6/7 =(100000-1100/7+1/49)×(10-1/7)+6/7 =1000000-100000/7-11000/7+1100/49-1/343+6/7 =1000000-(34300000/7-7700/49+1/343-294)/343 =1000000-34292007/343 =1000000-99976又239/343 =900024又104/343