12.4
For simple arithmetic like this, all the way up to calculus, I would recommend using wolframalpha.com to solve math problems.
4 times 7.75 is 31.
4 * 7 + 3 = 31 Hence 4 goes 7 times in 31.
124 ÷ 4 = 31
4 / 31 is equal to 0.129032
124
You must divide 124 by 31 to get the answer, which is 4. To check your answer, multiply 31 by 4, and the product will be 124.
31 ÷ 7 = 4 remainder 3
3.875
4! + (4 + 4!)/4 = 24 + (4 + 24)/4 = 24 + 28/4 = 24 + 7 = 31
31 ÷ 9 = 3 remainder 4
31
9/4 x 31/9 = 7 3/4 or 7.75