Question

What is the unit digit of 7^7⁷?​

Answer 1

Hello,

Explanation:

unit mean the unit digit of ...

`unit(7^0)=unit(1)=1\\unit(7^1)=unit(7)=7\\unit(7^2)=unit(49)=9\\unit(7^3)=unit(7^2)*7=unit(9*7)=unit(63)=3\\unit(7^4)=unit(7^3)*7=unit(3*7)=1\ just\ like\ unit(7^0)\\`

`\left \{ \begin {array}{cc}1&if\ n \in 4*\mathbb{N}\\7&if\ n \in 4*\mathbb{N}+1\\9&if\ n \in 4*\mathbb{N}+2\\3&if\ n \in 4*\mathbb{N}+3\\\end {array} \right.\\\\\\unit(7^{7^(7)})=unit(7^{(7^(7))})=unit(7^(823543))=unit(7^3)=3\\\\unit((7^(7))^(7)) =unit(7^(49) )=unit(7^(1))=7\\`

I have given 2 answers since i don't know what you mean with 7^7⁷.