Think about what you get by doing one operation. You can get any of these puzzles:

7 4 3 1 = 10 - that is, (5+2) 4 3 1
3 4 3 1 = 10
10 4 3 1 = 10
2.5 4 3 1 = 10
25 4 3 1 = 10 (exponentiating)
5 6 3 1 = 10
5 8 3 1 = 10
5 -2 3 1 = 10
5 0.5 3 1 = 10
5 16 3 1 = 10

and ten more.

Maybe you can see a solution to some of those simpler puzzles.. For instance, the second one could give 3 + 4 + (3x1) = 10. That would give a solution to the original puzzle of (5-2) + 4 + (3x1) = 10. You do not really need the parentheses on that one - sometimes you will.

There are lots more solutions - see how many you can find. Hint: you can always "lose" the 1 by multiplying, dividing, or exponentiating.

Bonus points (in my rating) for nontrivial use of exponents, or of division with a noninteger result!

Good Hunting!
RD