11.9595 rounding to the 3.dp?

What are all the codes for? Arithmetic does not use codes, so anything you write should be perfectly clear.

To round, look at the digit to the right. If that is 4 or less, drop it. If it is 5 or greater, then increase the target digit by 1. The third digit is 9 and the digit to the right is 5, so you increase the 9 to 10. Then carry the addition in the normal fashion.

11.9595 ~ 11.960 We write the third digit as zero so people will know that the number is rounded to that accuracy.

Rounding 11.9595 to the 3.dp would mean it is approximately 11.960