Round a divided number in Bash

Question

How would I round the result from two divided numbers, e.g.

3/2

As when I do

testOne=$((3/2))

$testOne contains "1" when it should have rounded up to "2" as the answer from 3/2=1.5

Answer 1

To do rounding up in truncating arithmetic, simply add (denom-1) to the numerator.

Example, rounding down:

N/2
M/5
K/16

Example, rounding up:

(N+1)/2
(M+4)/5
(K+15)/16

To do round-to-nearest, add (denom/2) to the numerator (halves will round up):

(N+1)/2
(M+2)/5
(K+8)/16