( 1).28/ 1\5

=28x5

= 140 (piece)

Answer: The big gear has 140 teeth.

(2).80/( 1-4\5)

=80/ 1\5

=80x5

=400 (weeks)

The pinion rotates 400 times per minute.

1490000 = 9000000

90000000/( 1- 1\46)

= 900000000 x46 \ 45

=(90000000x46)\45

=92000000 (person)

92 million people = 92 million people

A: There are about 92 million people in Henan.

/is the division symbol; \ Represents a score.