42/50 as a percentage is 84.00%. This value tells you how much of a whole the fraction represents when you look at it in terms of hundredths.
The fraction 42/50 can be reduced to 21/25, which is still the same amount. Whether you see it as a fraction, a decimal (0.84), or a percentage, the size of the part stays constant.
In everyday situations, 84.00% might describe a test score, a discount, or the portion of a project that’s finished. Knowing the percentage makes it easy to compare with other numbers that are also expressed out of 100.
