Can Macros change Character Attributes?

Howdy! I'm new to Roll20 and have a question about macros. I'd like to roll damage and then decrease HP by that amount, for an arbitrary token. Q1: Can we re-use values (like the result of the last die roll) in macros? Q2: Can macros change attributes? I know that I can do this with the API, and I have a Mentor subscription. I was just wondering whether it was possible doing macros... I'd say 75% of what I want to do is just doing a roll/calculation, and then adding or subtracting the result from an attribute. If there's a slick way to macro that, I'd rather do that than program API scripts. Thanks!

no, that sort of thing would require an api script called by a macro.

More specifically; the only value that the Macro system can store or modify is a Token's Turn Order, via the Tracker roll option &{tracker} (and even that value is write-only, you can't pull the value in as a variable) Otherwise, as Nobrodooh mention, Macros are entirely read-only.

You can , however, re-use the value of a roll query. /roll ?{Num Dice|1}d4 + ?{Num Dice} will only ask you for "Num Dice" once.