numberformat question

[jbv at souslelogo.com]

Hi list,
I am a bit lost :

    set numberformat to ".#########################"
    put -0.0000007347880794884118999 / 1000
-- returns -0.0000000007347880794884119  which is ok

    put -0.0000007347880794884118999 / 1000000
-- returns -0.0000000000007347880794884 -> also ok

    put -0.0000007347880794884118999 / 100000000
-- returns -0.0000000000000073478807949 -> still ok

    put -0.0000007347880794884118999 / 1000000000
-- returns 0 -> ?????

Any explanations ?
Thanks in advance.
Best,
jbv