∵3＜10＜4，
∴m=3，n=10-3，
∴m-n=3-（10-3）=6-10．
故答案为：6-10；
With a lot of problems _____, the newly-elected headmaster is having a hard time. [ ]
A. settled
B. settling
C. to settle
D. being settled
纳税人需变更主管税务机关或更改缴税账户必须重新签订三方协议。
