One way to tell that 675 is a multiple of 5 is to divide 675 by 5 and see if it comes out without a fraction. 675 divided by 5 = 135. Another way is to know that any integer ending in five is a multiple of 5.
84.375
42
2.5 divide by 67.5 = 0.037037037037037035
0.04
675
10.0089
225
675 divided by 9 is 75.
675
0.2
16.0714