Simplifying 21/4

How to reduce 21/4 to its simplest form

To simplify 21/4 we have to divide both numerator (21) and denominator (4) by their greatest common factor (GCF). In other words, writing a fraction in its simplest form means that both numerator and denominator can no longer be divided by the same whole number other than 1.

Result simplifying 21/4

Greatest Common Factor (GCF): 1

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Simplifying 21/4 step by step

Find the greatest common factor of 21 and 4

To simplify a fraction, look for the greatest common factor of the numerator and the denominator. The greatest common divisor of 21 and the 4 is 1. So this is already the simplest form of the fraction. So we cannot simplify this further.

If your fraction is improper, simplify it as a mixed number.

An improper fraction is a fraction that has a larger numerator than denominator. To simplify an improper fraction as a mixed number (a number that combines a whole number and a fraction) you have to determine how many times the denominator fits the numerator. In this case the denominator (4) fits the numerator (21) 5 times. The leaves us with a remainder of 1. Therefore we can rewrite the fraction like this:

(5 x 4) + 1

Simplify fractions

If a fraction is not yet in its simplest form, you can rewrite (reduce) it into a fraction where numerator and denominator are as small as possible. Try our simplified fraction calculator to simplify your fractions and find the greatest common factor (GCF).

Simplify fraction calculator

A fraction is irreducible (in its simplest form) when the numerator and denominator have no common factors other than 1. In that case the greatest common factor is 1.