Find the LCM of 12, 18?
Step 1: pick the highest of the given numbers of whom we have to find the LCM.
In the above example question, pick 18 as it is highest among 12 and 18.

Step 3: multiply the highest number to 2,3,4,… and so on till you find that number which can also be divided by the other number(s).
In the above problem, multiply 18 to 2 in your mind, it is equal to 36. Now check it whether it can be divided by 12. Since 36 can be divided by 12,
so 36 is the LCM of 12,18.

Find the LCM of 2, 3, 5?
Shortcut : pick 5 since it is highest number among the three. Now check it whether it can be divided by 2 and 3. 5 cannot be divided by 2 and 3. Now think of 5×2= 10 (since you know the table of 5). Check whether it can be divided by 2 and 3. It again cannot be divided. Now think of 15 then 20 then 25 then 30. Now 30 is that number which can be divided by 2 and 3.
So the LCM of 2, 3, 5 is 30.