Question

Find the unit digit. 15 x 12 x 16 x 20

Answer 1

Answer:

method:-

1. take the unit digit of 'a'.

2. now take the remainder of 'b' after dividing it by 4.(because you will see that unit digit repeat itself after 4th power), i.e. unit digit of 12^4 is same as 12^204.

NOTE:- remainder must be between 1-4.(0 not included, i.e. if number is divisible by 4 then replace the number by 4)

3. now replace the a^b with that number and carry on the process.

EX:-

13^14^15^16 after 14 divided by four we get the remainder 2 & unit digit of 13 is 3.

So, replace 13 by 3 and 14 by 2 and remain same. Then the above equation will become

(3^2)^15^16=9^15^16

now the unit digit of 9 is 9 & after dividing 15 by 4 we get remainder 3, so replace 15 by three.

now the above equation will be,

9^3^16 = 729^16

now repeating the steps we replace 729 by 9 and 16 by 4(remainder wil be zero since 16 is the perfect multiple of 4, but as i said earlier when th number is perfectly divisible by 4 then replace it by 4).

729^16 = 9^4(which is not that hard to find)

So, unit digit of 13^14^15^16 is

Step-by-step explanation:

How do I find Unit digit of 12131415 ?

What is the units digits of 131313 ?

What is the unit digit of 7^7^7?

What is the units place digit of (11^1) + (12^2) + (13^3) + (14^4) + (15^5) + (16^6).

Answer 2

Answer:

first we can multiply the all digits

15*12*16*20=15600

unit digit = last digit

so unit digit is 0