66/80 as a percentage is 82.50%. This number tells you how much of the whole the fraction represents when you think in terms of hundredths.
The fraction 66/80 can be simplified to 33/40, which is still the same amount of the whole. Whether you write it as a fraction or a percentage, it shows a solid majority—over four‑fifths of the total.
You might see this kind of conversion in school grades, test scores, or simple everyday measurements. Knowing that 66 out of 80 equals 82.50% helps you quickly understand the size of the part compared to the whole.
