63/84 = 75%
A value like 75% can show up in everyday life when a store advertises a sale, a student gets a score, or a weather forecast gives the chance of rain. It means the value covers most of the whole, but not all of it.
A quick way to picture it is to imagine a shape split into four equal parts, with three parts shaded. That makes it easy to estimate as about three-quarters of the total.
One common mix-up is treating 75% as 75 items, even when the total is a different size. It always describes a share of a whole, so the actual amount depends on what the whole is.