12.2. The sum of half and a third of a number is 7 units greater than its quarter. What is this number?

$$
(6-7 \text { grade })
$$
12.2. Let the desired number be denoted by $x$. Then

$$
\frac{1}{2} x+\frac{1}{3} x=\frac{1}{4} x+7, \text { from which } x=12
$$