I was working on a small app that needed to round some numeric values. For example, given a number such as 123.456789, I wanted to round this off to two decimal places such as 123.46. Why .46 instead of .45? Because the value is rounded at the n-th decimal place (.456 rounds up to .46).
MIT App Inventor does not have a function to do this sort of round off – well, not exactly. Actually, it has a formatting function that can accomplish the same thing but it is intended for converting numeric values to text strings.
I created a simple little program to demonstrate how this works, plus a couple of other methods to implement this feature.
Update: This post has been updated with thanks to Taifun for noting that App Inventor does have a “raise to a power function”. See below for more details and a link to his great web site!
User Interface View
The user interface prompts for a number, and the number of decimal places to which it should be rounded. Press the Round off number button to see the result.