There are as many fractions equal to 4/5 as there are numbers, but here are a couple that fit: 20/25 8/10 12/15 100/125 ...etc. Hope that answered your question :)
A fraction equivalent to 4/5 is 8/10, also 12/15. To find an equivalent fraction all you have to do is multiply the numerator and denominator by the same number.
