Number System Tips, Tricks and Shortcuts

Tips and Tricks to solve Number System Quickly

Trick to find the square of a Number :

25^{2}

we can write 25 as (20+5)

so, (20+5)^{2}

we will use the formula (a+b)^{2}

20^{2} + 5^{2} + 2*20*5

400 + 25 + 200 = 625 

56^{2}

square the first and second number = 5^{2}= 25  6^{2 } =36 = 2536

Then, multiply the given digit 5*6 = 30 and add 0 at then end = 300,

then multiply it by 2 = 300 * 2 = 600

add both the number = 2536 + 600 = 3136

Trick to solve the Square root of any number 

\sqrt{3136}

We have to see the unit digit of the number that is 6 and 6 is the unit digit of either the square of 4 or 6 

Now see the first two digits, 31 which comes between the square of 4 or 6, so we will take the number 5

Now multiply the number 5 by 4 = 20, it is not possible because it is way less than 31 
5*6 = 30, it is near 31

so 56 is the answer.

Tricks to find the factorial of any number 

n Factorial Formula
The formulas for n factorial are:

1. n! = n(n-1)(n-2)…………………….(3)(2)(1)
2. n! = n × (n – 1)!

7! = 7 * 6 * 5 * 4 * 3 * 2 = 5040

Trick to find the multiple square of a number 

\sqrt{5\sqrt{5}\sqrt{5}\sqrt{5}}

we will use the formula, x^{\frac{2^{n}-1}{2^{n}}}

n = number of digits in the square

we have four digits so, n =  4

5^{\frac{2^{4}-1}{2^{4}}}

5^{\frac{15}{16}}