The other answers are technically correct that a separable-verb should be treated and translated as one word to obtain the correct meaning.
On the other hand for a verb to be separable usually means that it consists of a prefix and a (base) verb. Both do have a meaning of their own. Though simply translating them separately does not necessarily yield a usable translation. It can however convey a basic meaning, especially if one keeps in mind to also consider figurative meanings.
For your concrete example abtragen
consists of tragen
which translates to to carry
and the prefix ab-
which translates to
Separable verb prefix, from.
ab- + fahren (“to leave”) → abfahren (“to depart from”)
Separable verb prefix that indicates removal or quitting, off.
ab- + spülen (“to rinse, wash”) → abspülen (“to rinse off, wash off”)
Separable verb prefix that indicates a downward movement, down.
Separable verb prefix that indicates from or of.
(source)
As such the meaning of abtragen
can be understood as to carry sth. away
or perhaps to reduce sth. [by carrying (some of) it away]
here to reduce
could also convey a sense of a downward movement, e.g. making the pile smaller.
In combination with the context of Schuld
(which should probably be understood as some kind of karmic debt
here) a possible translation is to pay of (karmic) debts
.
For more information on separable-verbs see also link.