how ? 312 x n = 24336
I need the method to know how to find the value

Try rearranging the problem and using division

n=24336/312 (24336 divided by 312)

you have to do the same to each side. So in this case you want to divide both sides by 312. This is allowed because it's the same as multiplying one side by 312/312 = 1, which does not change the answer.