It's difficult to work out the math problem.(写出同义句) ---- the math promblem is difficult.

问题描述:

It's difficult to work out the math problem.(写出同义句) ---- the math promblem is difficult.

是不是多打了一空?
= (To work out) the math problem is difficult.
哦,可以改成:
(Finding the solution/answer to) the math problem is difficult.