How did 'in-' + 'putare' compound to mean 'to attribute, credit to'?
I quote Etymonline on impute (v.):
early 15c., from Old French imputer, emputer (14c.)
and directly from Latin imputare "to reckon, make account of, charge, ascribe,"
from assimilated form of in- "in, into" (from PIE root *en "in")(2)) +
putare "to trim, prune; reckon, clear up, settle (an account)," from PIE *puto- "cut, struck," suffixed form of root *pau- (2) "to cut, strike, stamp" (see pave).
To wit, how did the prefix in- transmogrify "trim, prune; reckon, clear up" into "attribute, credit to'?
What exactly does the prefix 'in-' in imputare mean?