2、7.5× 2.3+ 1.9×2.5

3、 1999+999×999

1.2× 12+23×2

2. 15× 1 1+ 1 1× 18

3.85÷5- 15÷5

1. 1/3*(5*(2/3))

2.( 1+37%)*20

3.35/2*75%

4.30*(50/2)

5.(54+ 10%)/20

6.(25/3* 18)*30%

7.(2+70%)*40

8. 1/7*(98*( 1/4)*2)

9.25%*((23+2%)*4)

10.(30+20%)/2

1 1. 12*3/(25+20%)

12.30/(3+40%)

13.27/8* 16* 10%

14.(2/3)*(3+6)*( 1/2)

15.45*( 1/9)*24

16.(35+ 10%)*27

17.(45+50%)*3* 1/2

18.(43*20%)+(3*( 1/9))

19.27*(9*( 1/3))*5%

20. 14* 15%+25*8*( 1/4)

2 1.7*( 1/2)/49

22.( 1+48%)*2

23.(4*8- 12)*50%

24.(48/60%)/ 10

25.63*( 1/7)*30%