11.:3元
:15元
200÷15=13(本)......5(元)
68×3=204(元)
2.一小时=60分
60为一圈
即60÷10=6天
12. 12.43进位加0.01等12.44
6. 2n就行了!
5. 11个!
9. 30种车票!
8. 对
7. 9(2X-3)-2=5(2X-1)
18X-27-2=10X-5
18X-10X=27+2-5
8X=24
X=3
1. 男生35女生21
14. 14、1738 × 4 = 6952
1963 × 4 = 7852
3. 25元
4. 19.99*19.98-19.97*19.96
=(19.97+0.02)*19.98-19.97*(19.98-0.02)
=(19.97*19.98+0.02*19.98)-(19.97*19.98 19.97*0.02)
=19.97*19.98+0.02*19.98
19.97*19.98+19.97*0.02
=0.02*19.98+19.97*0.02
=0.02*(19.98+19.97)
=0.02*(20-0.02+20-0.03)
=0.02*(40-0.05)
=0.02*40-0.02*0.05
=0.8-0.01
=0.799
10. 2006÷7=286……4
13. 22人