well here is the more efficient proper way to show you so you understand.
step 1- Find the common G.C.F(Greatest common factor) in this case 5 as this number can go in both numbers
step 2- divide each number by 5. 5/5=1 and 10/5=2
step 3- Now you have your fraction simplified
Therefore your answer is 1/2.
Hope this helped:)