Decimals

Hi!

When creating a weighted mean score with piped text after a question, I got way too many decimals (3.999992939393939). That why I wanted to create a weighted mean with a maximum of 2 decimals. I read on one of these forums that you should use: $e{round(gr://SC_4OvT2vAMl4JC6ah/WeightedMean, 2 )}
So, that's what I did. Unfortunately, when I preview my survey this expression is invalid. I tried several things, with putting white spaces for instance.
Someone who can help with this?

Thanks!