Question 667972
Let the number be x.

Set up equation: {{{x-18=x/4}}}
Move eighteen over to begin to isolate x: {{{x=x/4+18}}}
Multiply all terms on both sides by four (LCD) to get rid of fractions: {{{x(4)=(x/4)4=18(4)}}}
Rewrite: {{{4x=x+72}}}
Bring the variable to one side.{{{3x=72}}}
Divide both sides by three to find x: {{{x=24}}}

Therefore, the number is 24.

Test it: 

A student subtracts 18 from a number.
{{{x-18}}}
{{{24-18}}}
{{{6}}}

The result is a quarter of the number.

Is {{{6 = (1/4)x}}}
Is: {{{6=24/4}}}
{{{6=6}}}

Since right side = left side, x = 24 is correct.