Susan adds 12 - 1/4 / number to get 22 what is her number

You answer this by isolating the variable. This means you work on the side where the variable is and do reverse operations to undo what was done in reverse "pemdas" order.

Start by translating and writing an equation:

Let x be the number

so:

12-1/4 x = 22

now subtract 12 from both sides. (because 12-12=0)

12-12-1/4 x = 22-12 (now simplify)

-1/4 x = 10

next you want 1 x, not - 1/4 x ... so to get to 1 you multiply both sides by the reciprocal of - 1/4 which is - 4/1

-1/4 * - 4/1 x = 10 * - 4/1 (multiply and simplify)

x = - 40