Let's start off with some basics to get you familiar with the term remainder.
7 / 3 = 2.333r or 2 remainder 1, because 3 fits into 7 twice, with 1 left over.
7/4 = 1 remainder 3
8/4 = 2 remainder 0, however we don't say remainder 0, we just say '2'.
So 860 / 14 = 61.428 (3DP). We can then multiply 61 by 14, and that difference will be the remainder.
14* 61 = 854.
860 - 854 = 6.
The remainder of 860 divided by 14 is 6