irrational number: a decimal fraction that does not end and does not repeat, like π.
least common multiple: the smallest number in which two or more numbers can multiply by
like fractions: fractions with the same denominator
mixed fraction: a fraction in this format:
numerator: top of the fraction
percentage: a constant % with value 0.01
proper fraction: a fraction where the format is like a mixed number, but only the right part of it. b