13+9= 14-7= 57+3=
40+30= 94-50= 89-8=
24+50= 90-30= 64-9=
10+30+40= 70-20-30= 19+(35-5)=
16+( )=25 24+( )=34 35+( )=39
80-( )=70 14-( )=8 50+( )=58
11+415 35-718+9 8+4898-40
31角3元 10个一1个十 5元-1元2角4元8角
44-4= 15-9= 30-20= 24+6= 85-5=
32-2= 60+6= 76-70= 89-9= 30+28=
15-76 14- 85 14-9 12-6
13-86 11-75 11-317-8
12-67 17-9 8 15-84+2
90-5+7= 77-(20+20)= 83-(60-10)=
6+2= 5+3= 9-5= 8-3=
36+2= 55+3= 49-5= 78-3=
月份
用电量/千瓦时
电费/元
4
50
25.00
5
80
38.00