How to calculate deviation, variance and standard deviation

Dispersion and variation Dispersion and variation are words that are used to describe the spread of values in a given set of data. Before you proceed, I recommend you check this post out, it's a prerequisite. Consider the set of examination marks of ten students in the  image below The marks are the same. They do not vary. No dispersion. Check the image below You can see that the marks are not the same. They vary. Their mean is 60. Some of the marks are greater than 60 while others are less. This set of marks has a greater variation or dispersion than those in table 1 Also, consider this table which shows a third set of marks of ten students. Although the mean is also 60. Don't know how to calculate mean? click here . However, it is clear that the marks are more varied than those in table 2. Thus, the marks here have a greater dispersion than the other marks. Let's talk about range. Range The range of a set of numbers is the difference between the ...

PICTURE: The Best Way Of Finding Lowest Common Factor With Simplified Calculations And Understanding Examples

LOWEST COMMON MULTIPLE (LCM)


As we discussed in our previous post, so shall we discuss here. We talked about HCF which stands for Highest Common Factor. We know you can only solve when you have the factor that is common in all given numbers. But LCM here is a different scenerio. 
We already know what a factor is, in terms of HCF.
Now, let's talk about multiple, in terms of LCM.

ueir efore we delve deeper into LCM, let's understand multiples to the fullest. Just like we understood factors

What is Multiple? Oo 9 of off 


Multiple of a given number are numbers that are formed by successfully multiplying the given number by counting number, 1, 2, 3, 4, 5, 6,....

Example
Multiples of 3 and 5 are found here

Multiples of 3 are 3 x 1 = 3, 3 x 2 = 6, 3 x 3 = 9, 3 x 4 = 12,....

Multiples of 5 are 5 x 1 = 5, 5 x 2 = 10, 5 x 3 = 15, 5 x 4 = 20,....

The multiples of 3 are 3, 6, 9, 12,...and so on.
The multiples of 5 are 5, 10, 15, 20,...and so on.

NB: best way to find multiples is adding the given number by itself.
i.e Multiples of 3 are 3, (3 + 3)=6, (6 + 3)=9, (9 + 3)=12, ... and so on.

Unlike Factors, Multiple doesn't have end. Keep adding till thy kingdom come, you're free.


Now that we have broad knowledge on Multiples, lets delve deeper into LCM itself.

METHOD I


Example I


Find the LCM of 2 and 3

                              Solution

NB: we use mutiples to find LCM while factors to find HCF

Multiples of 2: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20,...

Multiples of 3: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30,...

If you look closely, you can see there are numerous numbers that are common in both multiples. We can see 6, 12, 18,.... appeared in both multiples. But, the Lowest Common Multiple is 6.
Therefore, LCM of 2 and 3 is 6

Example II

Find the LCM of 10, 15 and 30

                             Solution

Multiple of 10: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100,...

Multiples of 15: 15, 30, 45, 60, 75, 90, 105,....

Multiple of 30: 30, 60, 90, 120, 150, 180,....

The common factors of 10, 15 and 30 are 30, 60, 90,..and so on. But the Lowest Common Multiple is 30.


METHOD II


Find the LCM of 10, 15, and 30

Here, we don't use Multiples, we use prime factors. As the name implies, LCM, you use the lowest number that can divide any of the given number. Here, the lowest number that can divide any of the given number is

NB: check the image below for simplified calculations





Want to know more about HCF and LCM? Then stick with us till the end.


Check out our previous lesson on HCF

Join our Facebook group

Like our Facebook page
,
Subscribe to our I'll il Channel

Check out some interesting post of ours here

Check out our table of contents here




Up ui.i

Comments