Why do we round up 0.5000 to 1 instead of rounding down to 0?

Question

Why do we round up 0.5000 to 1 instead of rounding down to 0?

In: 12

Answer 1

1,2,3,4 round down
6,7,8,9 round up

So 5 could go either way. It is just typical convention to decide to round up. However, anything larger than 5 should round up, included if you have additional place values, so if 0.5000001 rounds up then it’s neater to do 5 and up with 5 inclusive than exclusive.

However, there are different conventions; for instance, “bankers rounding” alternates if 5 rounds up or down. Negatives also cause different conventions, some round -0.5 to -1 and other to 0.