Arezzo contains many terms and functions to help with manipulating data in the rows and columns of repeating question groups (RQGs). You can refer to the current, next and previous row numbers, which helps you compare values across rows as well as columns. There are also functions which give the maximum, minimum, sum and average of a column of values. You can derive row numbers, or use arbitrarily complex expressions to create "labels" for each row in the group.
Click on the links below for further details.
You can also use the Arezzo Expression Builder to help you build your terms.