Let us proceed with an example :

465/200 = see both the numerator and denominator are multiples of 5...
hence in the numerator, see the 1st no it is 4 but it is smaller than 5..hence consider 46..if u divide 46 /5..u get the reminder 1.and quotient 9..hence the next no will become 15..thus 15/5,will give you 0 with quotient 3..henceĀ  the quotient will become 93..that is your numerator now..
then see 200, consider 200, if you divide 20/5, you get 0 as your remainder and 40 as your 40 is your denominator...

now your fraction becomes 93/40...since both of them do not have a common factor, you cannot simplify them anymore..