How many 3-digit numbers are divisible by
问题描述:
How many 3-digit numbers are divisible by
答
意思大概是,有多少个能被7整除的3位数,共128个,做法是,最小能被7整除的三位数是105,最大994,从105到994共890个数字,除以7等于127余点东西,所以是128个