divide 15 by 16 to get 0.9375.
In fact, it would be nice to memorize all fractions of 16:
1/16=0.0625
2/16=1/8=0.125
3/16=0.1875
4/16=1/4=0.25
5/16=0.5625
6/16=3/8=0.375
7/16=0.4375
8/16=1/2=0.5
9/16=0.5625
10/16=5/8=0.625
11/16=0.6875
12/16=3/4=0.75
13/16=0.8125
14/16=7/8=0.875
15/16=0.9375
This would be useful for any still living in the Imperial system, with lb/oz, fractions of an inch, etc.