How to Find the Least Common Multiple with LCM

LCM finds the smallest number all your values divide into — matching pack sizes and lining up repeating schedules.

You will learn to

• Match two pack sizes with no leftovers
• Convert the match into packs to buy
• Find when repeating schedules line up again

How it works

LCM(number1, [number2], …) returns the least common multiple — the smallest positive number that every value divides into exactly. Hot dogs come in 10s and buns in 8s, so =LCM(10,8) is 40: buy 40 of each (4 packs and 5 packs) and nothing is left over.

The same idea syncs anything that repeats. Buses every 12, 15 and 20 minutes all leave together again after =LCM(12,15,20) = 60 minutes. Add LCM(...)/1440 to a time to get the clock time of the next shared departure.

=LCM(B2,B3)