Video narration
For repeating routines, use LCM, the least common multiple. It means the smallest positive number that appears in both multiples lists. Multiples of 4 are 4, 8, 12. Multiples of 6 are 6, 12. The first shared repeat is 12, so the bell and reminder line up after 12 minutes. Now the choice is practical. If you're dividing supplies among teams, packing equal kits, or sharing snacks, ask: what is the biggest equal group size? Think GCF. If buses, bells, practices, or chores repeat on different schedules, ask: when will they meet again? Think LCM. So, which tool matters outside math class? For sharing fairly, GCF. For making repeating routines line up, LCM.