Question

What is unit digit of the following sum: 1 + 2^2 + 3^3 + 4^4 + 5^5 + 6^6?

Answer 1

Answer:

Step-by-step explanation:

1+ 4 + 27 + 256 + 3125 + 46656 = 50069

So, unit digit is 9.

Answer 2

Answer:

Digit at unit place of the sum of the given expression is 9.

Step-by-step explanation:

Given Expression: $1+2^2+3^3+4^4+5^5+6^6$

To find: Digit at unit place of sum of given expression.

Consider,

$1+2^2+3^3+4^4+5^5+6^6$

Digit at unit place of 1 = 1

Digit at unit place of 2² = 4

Digit at unit place of 3³ = 7

Digit at unit place of $4^4$ = 6

Digit at unit place of $5^5$ = 5

Digit at unit place of $6^6$ = 6

⇒ Sum of unit place digits = 1 + 4 + 7 + 6 + 5 + 6 = 29

Therefore, Digit at unit place of the sum of the given expression is 9.