Simplify 21/28

21/28 simplified is 3/4, after dividing the top and bottom by 7.

Result

Answer

\frac{21}{28} = \textcolor{#0b5c56}{\frac{3}{4}}

21/28 simplifies to 3/4.

  • Greatest common factor: 7
  • Decimal: \displaystyle 0.75
  • Percent: 75%
21/283/4

Same amount, fewer parts

Step-by-step solution

The problem

\frac{21}{28}

  1. Find the greatest common factor. List the factors of each:
    Factors of 21: 1, 3, 7, 21
    Factors of 28: 1, 2, 4, 7, 14, 28
    The greatest common factor (GCF) is 7.

    \text{GCF}(21, 28) = 7

  2. Divide the top and bottom by 7. Dividing both by the same number keeps the value the same.

    = \frac{21 \div 7}{28 \div 7} = \textcolor{#0b5c56}{\frac{3}{4}}

All the working together

\begin{aligned} &\frac{21}{28} \\[8pt] &= \frac{21 \div 7}{28 \div 7} && \textcolor{#5b6660}{\textsf{divide by 7}} \\[8pt] &= \textcolor{#0b5c56}{\frac{3}{4}}\end{aligned}

21/28 in other forms

Simplest form3/4
Greatest common factor7
Decimal0.75
Percent75%
Equal fractions6/8, 9/12, 12/16, 15/20

Fractions over 28 simplified

FractionSimplest formDecimal
1/28already simplest0.03571428…
2/281/140.0714285…
3/28already simplest0.10714285…
4/281/70.142857…
5/28already simplest0.17857142…
6/283/140.2142857…
7/281/40.25
8/282/70.285714…
9/28already simplest0.32142857…
10/285/140.3571428…
11/28already simplest0.39285714…
12/283/70.428571…
13/28already simplest0.46428571…
14/281/20.5
15/28already simplest0.53571428…
16/284/70.571428…
17/28already simplest0.60714285…
18/289/140.6428571…
19/28already simplest0.67857142…
20/285/70.714285…
21/283/40.75
22/2811/140.7857142…
23/28already simplest0.82142857…
24/286/70.857142…
25/28already simplest0.89285714…
26/2813/140.9285714…
27/28already simplest0.96428571…

Frequently asked questions

What is 21/28 in simplest form?

21/28 simplifies to 3/4. Divide the top and bottom by 7, their greatest common factor: 21 ÷ 7 = 3 and 28 ÷ 7 = 4.

What is the greatest common factor of 21 and 28?

The GCF of 21 and 28 is 7 – the biggest number that divides both with nothing left over.

Is 21/28 equal to 3/4?

Yes. Both are 0.75 (75%). Simplifying changes how the fraction is written, not its value.

More fractions to simplify

Any other fraction or mixed number: use the Simplify Fractions Calculator.