To increase (κερδαίνω kerdainō)

And when he who had received five talents approached, he brought another five talents, saying: Lord, you delivered five talents to me. Behold, I have increased it by another five. (Mt 25:20)

καὶ προσελθὼν ὁ τὰ πέντε τάλαντα λαßὼν προσήνεγκεν ἄλλα πέντε τάλαντα λέγων, Κύριε, πέντε τάλαντά µοι παρέδωκας· ἴδε ἄλλα πέντε τάλαντα ἐκέρδησα

Et accedens qui quinque talenta acceperat, obtulit alia quinque talenta, dicens: Domine, quinque talenta tradidisti mihi, ecce alia quinque superlucratussum.

There is a formula for profit in economics. The profit will be what is left after subtracting the incurred costs from the revenue. In today’s parable, the costs incurred by the servants are not explicitly mentioned, but in fact, they are the key here. Costs must be incurred in order to enjoy the profit. Our costs are our time, effort, focus, dedication, devotion, perseverance, fatigue, risk, courage, concentration, learning, effort of prayer, faith, hope, love, and many, many more.
We know the Polish proverb: “No pain, no gain.” Work brings profit, and as Jesus testifies, incurring costs brings profit and joy.