A number is divisible by 3 it the sum of its digits is divisible by 3. In this case, we have
[tex]1+6+2+4=13[/tex]
which is not divisible by 3. The nearest multiples of 3 are 1623 and 1626. If you divide these numbers by 3, you have
[tex]\dfrac{1623}{3}=541,\quad \dfrac{1626}{3}=542[/tex]
So, the result of our division is between 541 and 542.
If these numbers are too complex to divide, we have to choose easier numbers, but we will lose some accuracy. For example, we can see that 1624 is between 1500 and 1650, which are very easily divisible by 3. We have
[tex]\dfrac{1500 }{3}=500,\quad \dfrac{1650}{3}=550[/tex]
So, the result of our division is between 500 and 550. This is still true, but as you can see it is a much looser approximation than the one before.
