Write the greatest and the smallest 4-digit numbers using four different digits with the conditions as given:

(i) Digit 7 is always at units place.

(ii) Digit 4 is always at tens place.

(iii) Digit 9 is always at hundreds place.

(iv) Digit 2 is always at thousands place.

In a particular year, a company manufactured 8570435 bicycles and next year it manufactured 8756430 bicycles. In which year more bicycles were manufactured and by how many?

The sale receipt of a company during a year was ₹ 30587850. Next year it increased by ₹ 6375490. What was the total sale receipt of the company during these two years?

A machine manufactures 23875 screws per day. How many screws did it produce in the year 2016? Assume that the machine worked on all the days of the year.