Question 1161741
<br>
The difference between "a number" and "one-fourth of the same number" is "three-fourths of the same number".<br>
Since that difference is 21,<br>
{{{(3/4)x = 21}}}
{{{(4/3)(3/4)x = (4/3)(21)}}}
{{{x = 28}}}<br>
The number is 28.<br>
If you need to be formal with the first step of the solution, then...<br>
Let x = the number<br>
Then
{{{x - (1/4)x = 21}}}
{{{(3/4)x = 21}}}<br>
Then proceed as above.<br>