The wrong answer is the product of the decimal number

Question

1.005*1000=1004.99999 why?
and (1.003 or 1.005 or 1.007 or 1.009)*1000 ?

1003/1.003=1000.0000000000001 whay?

erorr number (1.003 1.005 1.007 1.009) in * and / its Bug ?

1.005*1000=1005
1003/1.003=1000