Question

Please tell the LCM of the following -​

Answer 1

Below.

Explanation:

I won't do all of these for you but I'll show you the general method.

First write each number as prime factors.

For example number 7:

LCM of 24 and 34.

24 = 2 * 2 * 2 * 3

34 = 2 * 17

The LCM is the multiple of all these factors EXCEPT if there is a duplicate number you only use it once.

There is one duplicate here - the 2 ( in bold) so we only use this once.

So the LCM = 2 * 2 * 2 * 3 * 17 = 408.

Number 1:

13, 25

13 = 13

25 = 5 * 5

There are no duplicates so the LCM = 13 * 5 * 5 = 325.

Number 18:

15, 84

15 = 3 * 5

84 = 2 * 2 * 3 * 7

Number 3 is common to both sets so it is only used once:

LCM = 2 * 2 * 3 * 5 * 7 = 420.

Number 40:

18, 48

18 = 2 * 3 * 3

48 = 2 * 2 * 2 * 2 * 3

There are 2 sets of duplicates here, 2 and 3 .

LCM = 2 * 2 * 2* 2 * 3 * 3 = 144.

Answer 2

Explanation:

2) 24 = 2 *2*2*3 = 2³ * 3

54 = 2*3*3*3 = 2 * 3³

LCM = 2³ * 3³ = 8*27 = 216

12) 14 = 2 *7

25 = 5*5 = 5²

LCM = 2*7 * 5² = 14*25 = 350

37) 12 = 2*2*3 = 2² * 3

32 = 2*2*2*2*2 =2^5

LCM = 2^5 * 3 = 32*3 = 96

LCM -> common number with highest power and the rest all numbers