For example, lets take [tex] \frac{25}{100} [/tex]
We need to first factor the numerator and denominator to find the common numbers which we can simplify it by.
[tex] \frac{25}{100} = \frac{5 \times 5}{5\times 5\times 4} [/tex]
If we divide by 5 x 5 on both the numerator and denominator because both of them have it in common, we will get the simplest form.
[tex] \frac{5 \times 5\div 5 \div 5}{5\times 5\times 4\div 5\div 5} = \frac{1}{4}[/tex]