=0.000000000031*0.000000007几位小数
问题描述：
=0.000000000031*0.000000007几位小数
答
因为0.000000000031是12位小数,0.000000007是9位小数,两数相乘,小数位数应该是：12+9＝21位.
=0.000000000031*0.000000007几位小数
因为0.000000000031是12位小数,0.000000007是9位小数,两数相乘,小数位数应该是：12+9＝21位.