pomnožiti

1. (in maths) to multiply
   Pomnoži tri sa pet i dobićeš petnaest. — Multiply three by five and you'll get fifteen.
   Cenu po kilogramu treba pomnožiti težinom. — The price per kilo needs to be multiplied by the weight.
2. to multiply; to increase many times over
   Za deset godina je pomnožio svoje bogatstvo. — In ten years he multiplied his wealth.

The multiplier usually follows sa + instrumental: pomnožiti dva sa tri.