Question

Write the smallest digit and greater digit in the blank space of each of the following number so that the number formed is divisible to by $3$.
$\underset{–}{}6724$

Answer 1

Since, if a number is divisible by $3$, then it is divisible by sum of all the digits of the number.

Sum of digits $=6+7+2+4=19$

Now, lets check the required smallest digit,

$19+0=19$ ---Not divisible by $3$

$19+1=20$---Not divisible by $3$.

$19+2=21$---Divisible by $3$.

So, the Smallest digit that we can add to the sum to make it multiple of $3$ is $2$.---(1)

Now, lets check the required greatest digit,

$19+9=28$ ---Not divisible by $3$

$19+8=27$---Divisible by $3$.

So, Greatest digit that we can add to the sum to make it multiple of $3$ is $8$. ---(2)