There are a few ways you can alter the display features of metric values. To access these options click on the plus button found left of the metric name in the visualisation widget. This will reveal the metric options available:

Show Split Column

Ticking the "Show Split Column" box will reveal the metric split field adjacent to the selected metric field. This displays how much of that metric is attributed to that dimension value from the total - displayed as a percentage.

Unit Formatting

The "Full" option will display the entire number with commas to seperate the thousands.

The "Formatted" option will round the metric value to the nearest base unit selected. For example to the nearest thousand, million or billion. If "none" is selected the app will recognise the most sensible base unit to round to. These can be selected in the "Base Unit" dropdown:

Furthermore, you can select the number of decimal places you would like to round to and the type of rounding - soft or hard.

Soft rounding (recommended) rounds a value up to the number of decimal places selected.
Hard rounding performs a string truncation on the number.