Question

The digit in the units place in the number $7^{289}$ is

• A. 9
• B. 7
• C. 1
• D. 3

Answer 1

Answer: (B)

Since, $7^1=7,7^2=49,7^3=343,7^4=2401$
Similarly, the next higher power of 7 comes out the same digits in the units place respectively.
$\therefore$ digit at units place in $7^{289}=$ digit at units place in ${\left(7^4\right)}^{72}\cdot 7$
$=$ digit at units place in $1\cdot 7$
The units place digit in $7^{289}$ is 7