And that's the culprit. Due to the binary interpretation of REAL and FLOAT datatypes

1 / 2^n + 1 / 2^(n+1) + 1 / 2^(n+2) + 1 / 2^(n+3) + ...

the value may not be stored exactly as you want. So you are left with two choices

1. Keep REAL and learn to live with it

2. Change to decimal and get what you want, all the times.