Answer: adding

AnswerCrossword Clue
ADDING

Calculating endeavor

ADDING

Tacking on

ADDING

Kind of machine

ADDING
Hitting the + key
ADDING
Abacus activity
ADDINGPutting two and two together
ADDINGPutting in
ADDINGDoing the math, in a way
ADDINGThrowing in
ADDINGFunction of a comptometer.
ADDINGSupplementing.
ADDINGFooting (up)
ADDINGArithmetic chore
ADDINGKind of office machine
ADDINGArithmetic task
ADDINGSum problem?
ADDINGArithmetic assignment
ADDINGChild's arithmetic lesson
ADDINGAction for calculating people?
ADDINGTotaling
ADDINGCalculator job
ADDINGSumming
ADDINGSimple arithmetic
ADDINGSummer job?
ADDINGIncreasing
ADDINGMaking two and two four
ADDINGAnnexing
ADDINGDoing sums
ADDINGPutting on
ADDINGJob for the summer?
ADDINGAccountant's work
ADDINGPerforming a simple operation
ADDINGKindergarten math lesson
ADDINGContributing (to)