Answer:
There are many answers to this question like:
7x6
21x2
84/2
27+15
Explanation:
If 30+12=42, all you really have to do is check each answer to see if it either adds up to 42, multiplies to get 42, divides to get 42, or subtracts to get 42.
6(5+2)
3(10+4)
These are just a couple of equivalent sums, I am assuming this is a sort of short response and not a multiple choose so i believe you can use this.
3.5m questions
4.4m answers