Definition of LCM

LCM stands for least common multiple. In mathematics, LCM of two numbers 100 and 70, is defined as the smallest positive integer that is divisible by both. It is written as LCM(100, 70).

Properties of LCM

  • The LCM of two given numbers is never less than any of those numbers. Eg- LCM of 100 and 70 is 700, where 100 and 70 are less than 700.
  • LCM is associative which means LCM(100, 70) = LCM(70, 100).
  • LCM is commutative which means LCM(a, b, c) = LCM(LCM(a, b), c) = LCM(a, LCM(b, c)).
  • LCM is distributive, which means LCM(ab, bc, ad) = d * LCM(x, y, z).
  • The LCM of two or more prime numbers is their product.

Steps to find lcm of 100 and 70 by Listing Method

Example: Find lcm of 100 and 70 by Listing Method

  • Multiples of 100: 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, 2100, 2200, 2300, 2400, 2500, 2600, 2700, 2800, 2900, 3000, 3100, 3200, 3300, 3400, 3500, 3600, 3700, 3800, 3900, 4000, 4100, 4200, 4300, 4400, 4500, 4600, 4700, 4800, 4900, 5000, 5100, 5200, 5300, 5400, 5500, 5600, 5700, 5800, 5900, 6000, 6100, 6200, 6300, 6400, 6500, 6600, 6700, 6800, 6900, 7000
  • Multiples of 70: 70, 140, 210, 280, 350, 420, 490, 560, 630, 700, 770, 840, 910, 980, 1050, 1120, 1190, 1260, 1330, 1400, 1470, 1540, 1610, 1680, 1750, 1820, 1890, 1960, 2030, 2100, 2170, 2240, 2310, 2380, 2450, 2520, 2590, 2660, 2730, 2800, 2870, 2940, 3010, 3080, 3150, 3220, 3290, 3360, 3430, 3500, 3570, 3640, 3710, 3780, 3850, 3920, 3990, 4060, 4130, 4200, 4270, 4340, 4410, 4480, 4550, 4620, 4690, 4760, 4830, 4900, 4970, 5040, 5110, 5180, 5250, 5320, 5390, 5460, 5530, 5600, 5670, 5740, 5810, 5880, 5950, 6020, 6090, 6160, 6230, 6300, 6370, 6440, 6510, 6580, 6650, 6720, 6790, 6860, 6930, 7000

Hence, LCM of 100 and 70 is 700.

Steps to find LCM of 100 and 70 by Common Division Method

Example: Find lcm of 100 and 70 by Common Division Method

2 100 70
2 50 35
5 25 35
5 5 7
7 1 7
1 1

Hence, LCM of 100 and 70 is 2 x 2 x 5 x 5 x 7 = 700.

Steps to find lcm of 100 and 70 by Formula

Example: Find lcm of 100 and 70 by Formula

  • GCF of 100 and 70 = 10
  • LCM of 100 and 70 = (100 x 70) / 10
  • => 7000 / 10

Hence, LCM of 100 and 70 is 700.

Examples

Ram and Deepika are running on a circular track. They start at the same time. They take 100 and 70 minutes respectively to go round once. Find at what time they will run together?

Ram and Deepika are running on a circular track. They take 100 and 70 minutes respectively to go round once. We need to find out at what time (minimum) they will run together again. For this we need to find the LCM of 100 and 70.
So, LCM of 100 and 70 is 700.

A shopkeeper sells candies in packet of 100 and chocolates in packet of 70. What is the least number of candies and chocolates Annie should buy so that there will be one candy for each chocolate?

The least number of candies and chocolates Annie should buy so that there will be one candy for each chocolate we need to find the lcm of 100 and 70.
So, LCM of 100 and 70 is 700.

What is the relation between LCM and GCF( Greatest Common Factor)?

Greatest common factors or gcf of 100 and 70 is GCF(100, 70) * LCM(100, 70) = (100 x 70) / GCF(100, 70) = 700.

Sammy's company prints 100 textbooks at a time. Daniel's company prints textbooks in sets of 70 at a time. According to a survey done by a committee, both companies printed the same number of textbooks last year. Find the least number of books that each company would have printed.

To find the least number of textbooks that each company could have printed we need to find the LCM of 100 and 70.
So, LCM of 100 and 70 is 700.

Mary exercises every 100 days and Nikki every 70 days. They both excercised today. How many days will it be until they excercise together again?

The problem can be solved using LCM, because we are trying to figure out the least time until they excercise together again.
So, LCM of 100 and 70 is 700.

Find the least common multiple of 100 and 70.

Least common multiple of 100 and 70 is 700.

Find the least number which is exactly divisible by 100 and 70.

Least number which is exactly divisible by 100 and 70 is 700.