有五个数平均数为9,若把其中一个数改成1,那么这五个数的平均数为8,这个改动的数原来应该是______.
9×5-8×5+1
=45-40+1
=6;
故答案为:6
什么是轴测图
Teachers always expect their students to realize that hard work ________. [ ]
A. puts off
B. gives off
C. pays off
D. sees off