You're getting a mix of exponential (scientific) and decimal notation.

When I did the calculations on my computer for a few key numbers, using SpeedCrunch.

1/5666.1 =** 0.0001764882370590000176488237059**0000 176488237059000

1/5666.5 = **0.000176475778699373510985617224036**00 105885467219624

1/5666.9 = **0.0001764633220985018263953837194939**0 319222149676190

1/5666.0 = **0.00017649135192375573596893752206141** 899046946699612

1/5666.2 = **0.00017648512230418975680350146482651** 512477498146906

Note that the digit following your displayed number is a ZERO.

When Windows rounds the number, it apparently is getting a whole number, and thus chooses to display it in decimal form. On the other numbers, the digit following the last displayed digit is non-zero, and thus it is choosing scientific notation.

Actually, when I put it into courier font, it is clear that you loose a couple of digits on the trailing end due to the zeros. I.E. It isn't just the digits following the last displayed digit, but rather if the last displayed digit is full precision, then it is written in scientific notation. If it is not, then it would be written in decimal notation.

I presume it also has to do with the number of leading zeros that you have (4, including the one before the decimal). (e-4) takes 3 spaces. I think this means that you can actually display one extra digit of precision in scientific notation than you can display in decimal notation.

For the three numbers displayed, that extra digit of precision is irrelevant.

If you had 3 leading zeros (10/5666.0) the precision in decimal and scientific notation would be the same, so I would predict that they all would be displayed in decimal notation.

If you had 5 leading zeros (0.1/5666.1, 0.1//5666.5, & 0.1//5666.9), at least the first one will be in decimal notation. Probably the second, but definitely not the third. At least that would be my guess.