round-off issue?

I can't figure out why the floor wont come to 1752?

    >> 3.501/40*20*10^3+1.5

    ans =

        1.752000000000000e+003

    >> floor(ans)

    ans =

            1751

Answer 1

[Fangjun Jiang]

Rounding error caused by floating point calculation.

>> 3.501/40*20*10

ans =

17.504999999999995

[Jan]

sprintf('%.13f', 3.501/40*20*10^3+1.5)

>> 1751.9999999999998

sprintf('%.12f', 3.501/40*20*10^3+1.5)

>> 1752.000000000000

[Fangjun Jiang]

Thanks, Jan! That's even better to explain the problem!