množiti

1. (in mathematics) to multiply
   Deca u drugom razredu uče da množe. — Children in second grade learn to multiply.
   Kad množiš broj nulom, dobiješ nulu. — When you multiply a number by zero, you get zero.
2. (množiti se) to multiply; to increase; to breed
   Problemi se množe iz dana u dan. — The problems are multiplying day by day.
   Bakterije se brzo množe na toplom. — Bacteria multiply quickly in warm conditions.
3. to increase; to multiply
   Takve odluke samo množe nezadovoljstvo građana. — Decisions like that only increase public discontent.

"Multiply by" is expressed with sa + instrumental: množiti tri sa pet.