You can use aggregate functions such as sum or count, as well as arithmetic and other built‑in functions, to calculate subtotals and other summary values to be printed in a report. Many Report-Writer statements accept expressions. For example, you can specify an aggregate, arithmetic operation, or function in the .print statement for immediate printing of the calculated value. Alternatively, you can use an expression containing the operation in a .let statement to assign the calculated value to a variable prior to printing, in case you want to use the result in additional calculations.