Determine whether an estimated value or an exact value is more appropriate to use : the cost price of a smart phone

Determine whether an estimated value or an exact value is more appropriate to use : the number of leaves of a tree

Determine whether an estimated value or an exact value is more appropriate to use : tthe number of passengers in a lift

Determine whether an estimated value or an exact value is more appropriate to use : the population of a country

Round off 16.46 to ones place. (type the number)

Round off 427 to ten place. (type the number)

By front-end method, find the estimated value of 3 573

By front-end method, find the estimated value of 17

Round down 12 580 to the thousand place.

Round down 67.5 to the ten place.

Round up 2580 to the thousand place.

Round up 3.22 to the one place.

A book consists of 120 pieces of paper. The weight of each piece of paper is 4.98 g. Estimate the weight of the book.