Per Hundred

The word percent means "per hundred." So 25% is just another way to write 25 out of 100, or the fraction 25/100.

To turn any fraction into a percentage, divide the top by the bottom, then multiply by 100. That gives 3/4 = 0.75 = 75%. You are simply rescaling the fraction so its denominator is 100.

Why bother? Because a shared base makes comparison instant. Is 7/20 bigger than 12/35? Hard to say at a glance. But as 35% vs 34.3%, the winner is obvious. Percentages are fractions made comparable.