It's clever for him to work out the difficult math problem.单句改错

It's clever of him to work out the difficult math problem.
句型it's adj +for/of sb to do sth
如果这个形容词可以修饰人，就用of，如果不能用来修饰人，就用for，句中clever可以修饰人，所以用of

clever———hard

It's clever of him to work out the difficult math problem.。 it's adj +for/of sb to do sth。 用of是指这个人很聪明所以to，结论他可以做出这道难题。而不是for,for是指物，那么便会成：这道题是这么聪明、对于他，去、做出这道难题。of修饰人,for修饰物。

It's easy for him to work out the difficult math problem.

it's +adj +for/of sb to do sth
当形容词是指人的品质方面的,如bad坏,kind,distingue高尚的等等,则应该用of
其他情况下一般用for.
所以此句应把for改为of