What number should i multiply 1 1/4 by to get 7/12

Let's take our given information and transform it into numbers. We will let x equal the "mystery" number we need to find. Here is our equation:

Now, all we need to do is convert the mixed fraction into an improper fraction:
 
Now, just multiply the reciprocal of 5/4 with 7/12, giving us:

Finally, just straight up multiply to get an answer of x = 28/60, which can be simplified down to x = 7/15. Therefore, the number you have to multiply 1 1/4 to get 7/12 is 7/15. Hope this helped!