Hi Pat,
Great question! You actually cannot control what decimal you're rounding to, but there's a pretty easy workaround. Let's say you have a number 2.576 that you want to round to 2.6. I will take 2.576, multiply it by 10, round, and then divide by 10. See attached image.
You can also use a Number Input object, and set it to read only and use 1 decimal place, but this doesn't actually round, it only truncates - so 2.576 would become 2.5. However, using a Number Input object set to read only is a great way to format your values.
https://www.screencast.com/t/mhmm7r6q8sW
Hope that helps!