The Greek arithmeó means to count or to number — to enumerate items in sequence. It is the verbal form from which we get the English word 'arithmetic.'
Arithmeó appears three times in the New Testament, all in Matthew 10:30, Luke 12:7, and the parallel Matthew 10:30, where Jesus declares that even the hairs of our head are all numbered by God. This extraordinary statement of divine attention and care — God knowing and tracking even the most trivial details of each person — is offered in the context of fear and persecution. When the disciples face threats, they are reminded that they are known completely and cared for specifically. The God who numbers the stars (Psalm 147:4) and names them also numbers each hair on each beloved child.