you have to find a common factor, the most obvious and easy to do in your head is 2. divide both parts by two to leave 18 over 19. those two numbers have no common factors so the answer is 18/19.
the idea is present fractions in their simplest form. for example 25/100 is the same 1/4
You cannot simplify 31 over 36 because 31 is prime.
you do
Yes
36/8 = 9/2
divide by 19
2/3
one over two
36/42
36/38 = 18/19
36/24=3/2
45/36 = 5/4
17/18