Question

What will be the unit digits of the square of the following numbers?

$39$, $297$, $5125$, $7286$

• A. $9,9,1,6$
• B. $1,9,5,6$
• C. $9,2,5,2$
• D. $3,2,5,7$

Answer 1

Answer: (B)

$1,9,5,6$

$\left(a\right)$The numbers with unit's digits $1$ or $9$ has its square as $1$

$\therefore$ the unit's digit of square of $39$ is $1$

$\left(b\right)$The numbers with unit's digits $3$ or $7$ has its square as $9$

$\therefore$ the unit's digit of square of $297$ is $9$

$\left(c\right)$The numbers with unit's digits $5$ has its square as $5$

$\therefore$ the unit's digit of square of $5125$ is $5$

$\left(d\right)$The numbers with unit's digits $4$ or $6$ has its square as $6$

$\therefore$ the unit's digit of square of $7286$ is $6$