Numbers can be divided into periods of 3 digits each.
These periods are sectioned by dividing 3 digits each starting from right to left
If we take the number 4,083,817 lets divide it into 3 digits starting from right to left
period 1 - 817
period 2 - 083
period 3 - 4
period 1 is known as the units period
period 2 is thousands period
period 3 is millions period
therefore digits in the 1st period belong to the units period
digits in the first period or units period are 817
answer is 817
