[web2py] What am I doing wrong

[Kenneth Lundström]

    test1 = 250.90
    test2 = 47.90
    test3 = 99.90

    test4 = test1 + test2 + test3

    test5 = 398.70

    test6 = test5 - test4

    return test6

This returns -5.68434188608e-14 not 0 as you would expect, or?


Kenneth