408/408 = 100%
A fraction like 408/408 shows up when every item in a group is complete, correct, or accounted for. For example, if all 408 students submit a permission form, the school can report that 100% of the forms were received.
You can picture 408/408 as one full circle, a completely filled progress bar, or every seat in a section being occupied. Since the top and bottom numbers are the same, you can quickly recognize that the value is a whole, or 100%.
A common mistake is thinking that the large numbers make the fraction greater than 100%. The numbers may be large, but because the numerator and denominator match exactly, the fraction represents the entire amount and not more than the whole.