The answer to your question would be.... 100 ways!
This is so because a quicker and easier way I like to use in these kinds of problems is to multiply the number of ways times the number of operations. So, I did 25 (number of ways) times 4 (number of equations) to find out all the possible combinations to express 50 using all 4 operations including fractions, and decimals!!
I really hope this helps you out!!!