12÷3+7= (76-36) ÷8= 45+21÷3= 18÷9-2=
35-21+24= 25- 5×3= 18÷(9- 3)= 4-1×3 =
56+29= 74+20= 43+25= 65-32=
38+42= 88-49= 57-29= 48+36=
770-570= 400-270= 690-380= 470+360=
640÷8= 63÷3= 350+406= 500-123=
15×6= 10-8.6= 100×5×0= 2+18×2=
86+45= 370+130= 43-17= 284+455=
90-27= 324+74= 756-239= 498+303≈
980-72÷9= (436-388)÷8= 3×8+74= 507-291≈
65+48= 75-26= 39+41= 230+470=
820-500= 45+56= 70-38= 46+32=
308+425842 963-689374 428+79479+28
744-351400 83-2657 561-378561-372
①0.4x=3.6
②x﹣x=70
③1.6:x=0.8:0.4
④=