What is the GCD of 18 and 24?

What is the LCM of 8 and 12?

What is the LCM of 6 and 14?

Two runners jog in loops of 8 minutes and 12 minutes. How many minutes until they are jogging together again?

Two gears turn. One completes a turn every 15 seconds, the other every 20 seconds. How long until they both start together again?

The GCD of two numbers is 7. One number is 28 and the other is unknown. Their LCM is 84. What is the other number?

Three lights blink every 4, 6, and 10 seconds. How many seconds until they blink together?

A light blinks every 5 seconds, another every 8 seconds. How many seconds until they blink together?

A ferry crosses the river every 12 minutes. Another ferry crosses every 18 minutes. How many minutes until both are at the dock together?

Two fans rotate every 40 and 60 seconds. How many seconds until they rotate together again?