In the Indian system of numeration, on the left of the thousands period is the period.

Fill in the blanks.

In the International system of numeration, on the left of the thousands period is the _____period.

Find the estimated values and then quotient up to the nearest $10$.

$568÷28$

Find the estimated values of numbers and then their quotient up to the nearest $10$.

$987÷111$

Round off the number $4578521$ to the nearest thousand.

Round off the number $4578521$ to the nearest ten thousand.

Round off the number $4578521$ to the nearest lakh.