Jasonkiln

dividing the numerator and the denominator by the largest number that can divide into both numbers exactly.

That is the most basic way to simplify basic fractions. For example expressions/exponents would not completely work.

Ex: 10/5 = 2/1 or just 2
 

10/35 = 2/7

If you would like to simplify exponents and expressions there are other ways to approach that

As stated in the question,  "How many different combinations of 3 blocks can be selected from that set so that no two are in the same row or column?"

Order does matter

Answer was incorrect in the app and I also don't understad tying the the two c's together

12!/3!*3!*3!*3!

would that be correct?

Thanks! I set up a venn diagram as you said and got the same answer!!

I also realized its not 64 maybe there was a repeated digit somehwere?

Thanks for listing them out but do you know any way to do it without listing them out? Because that could take a while

I got 72 for the second one but it is in correct
2*5*8 = 80
80-8
72