*Magic: 1*

Hey!! Do you have any idea about *amicable numbers*? Just keep in mind **220 **and **284 **are amicable or you can say friend numbers!! How? That should be the big question. I am now explaining it to you.

See, the factors of 220 are : 1,2,4,5,10,11,20,22,44,55,110

Now if you add them together the summation becomes 284!!

Again, the factors of 284 are: 1,2,4,71,142

If you add them together the summation becomes 220!! Isn't it interesting?

*Magic: 2*

Now, do you know what *perfect numbers* are?

These are such numbers, the sum of those factors (except the number itself), is equal to the nunber It's elves!!

Example : **6,28,496**

The factors of 6 are 1,2,3 and 6. Now if you add 1,2 and 3 the summation becomes 6!!

Again, the factors of 28 are 1,2,4,7,14,28. Niw if you add the factors except 28 it becomes 28!! Same in the case of 496.

**Note : **

Always remember the sequence of prime numbers from 1 to 100. This is

**4422-322-321**, Total = 25 prime numbers.

*Magic: 3*

Do you know how to recognise a *prime numbers*??

Let, p be a given number and let n be the smallest counting number such that **n^2 >=p**. Now test whether p is divisible by any of the prime numbers less than or equal to n. If yes, then p is not Prime number, otherwise p is prime.

Example : let 811. We know that (30)^2 > 811. Now prime numbers less than 30 are 2,3,5,7,11,13,17,19,23,29. Clearly none of this numbers divides 811.

Therefor, 811 is a prime number. Try 137 yourself!!

Again, let 437. We know that (21)^2 > 437. Now prime numbers less than 21 are 2,3,5,7,11,13,17,19. Clearly 437 is divisible by 19. So 437 is not a prime!! Interesting, isn't it??

*Magic:4*

There is a arithmetic sequence of five numbers!! Can you imagine?

See, **5,11,17,13,29**!! The difference is 6 every time? Do you now it before?

So, that's all for today. Play with numbers. It will keep Your brain so active and fresh.

**Stay tuned. Happy Numbering. 🧠✍**