5/12 as a percentage is 41.67%. This number tells you how much of a whole 5 parts out of 12 represent when you look at it in terms of 100.
The fraction 5/12 can also be thought of as five slices of a pizza that has been cut into twelve equal pieces. If you ate all five slices, you would have consumed about 41.67% of the pizza.
Knowing the percentage makes it easy to compare with other numbers, like a discount of 40% or a test score of 45%. It’s a quick way to see that 5/12 is just a little more than two‑fifths of a whole.