very annoying bug. x = 6.12 10^(-31) does not display negative exponent. But x = 6.12 10^(31) displays OK. So many bugs in Mathematica Cloud version, I'm totally disgusted with this product.
Curiously, Times[6.12,Superscript[10,-31]] does render the exponent correctly.
It's very important to remember the both the Wolfram Programming Cloud and Mathematica Online are both beta products, and not all functionality can be expected to work yet. Porting complex desktop software to the cloud is not a simple task.