Data type sequence error:Dictionary

[BlackWhite]

Source code:
d={"x":42,"y":3.14,"z":9}
d.keys()
['y','x','z']                 //Why y in font  of x
d.values()
[3.1400..01,42,9]            //Why 3.140000000000000001 should not have 1 in
the end

Why this happened?