Question

Determine whether $723840$ is divisible by $2$, $4$ or $8$

Answer 1

Step 1 - Checking the divisibility by $2$

A number is divisible by $2$ if its last ( unit’s) digit is divisible by $2$ I.e., if its last digit is $0,2,4,6,8$

The number $723840$ has $0$ as its last digit.

Therefore, $723840$is divisible by $2$.

Step 2 - Checking the divisibility by $4$

A number is divisible by $4$ if the number formed by its last two ( unit’s and ten’s ) digits is divisible by $4$.

The number formed by last two digits of $723840$ is $40$ , which is divisible by $4$. $\left[\because 4\times 10=40\right]$

Therefore, $723840$ is divisible by $4$.

Step 3 - Checking the divisibility by $8$

A number is divisible by $8$ if the number formed by its last three ( unit’s , ten’s and hundred’s ) digits is divisible by $8$.

The number formed by last three digits of $723840$ is $840$ , which is divisible by $8$ $\left[\because 8\times 105=840\right]$

Therefore, $723840$ is divisible by $8$.

Hence, $723840$ is divisible by $2,4$and $8$.