(1

1

1998

×8.12+5

31

75

÷

2

3

×8

1997

1998

)÷4

11

48

=（1

1

1998

×

203

25

+

406

75

×

3

2

×8

1997

1998

）×

48

203

=（1

1

1998

×

203

25

+

203

25

×8

1997

1998

）×

48

203

=

203

25

×（1

1

1998

+8

1997

1998

）×

48

203

=

203

25

×10×

48

203

=19.2．