Ruby - mathematics operations

Question

I tried a few minutes ago simple math operation

<%=((3+2+1)/100).round(8)%>

The result is 0.06, but the result of the ruby code above is 0.0. I would expect the result should be 0.060000.

Why not? Thanks

Answer 1

(3+2+1)/100 

is 0 because the division is integer. Try

(3+2+1)/100.0

You see, if both arguments of / are integer, the result of the division is an integer (the whole part). If at least one of the arguments is floating-point, then the result is also floating-point.

Answer 2

The dreadful integer arithmetic attacks again!

When you calculate ((3+2+1)/100), since all the operands are integers, Ruby uses integer arithmetic rather than floating point arithmetic.

If you do 7/100 it will also return 0, as it's rounded down to the nearest integer, which is 0.