7.1,6.2,5.3,4.4,,。
12×50= 40×30= 25×40= 84÷7=
306÷3= 124×2= 102×5= 160÷4=
+ = 1- = - = + =
①(++)×30
②7.2×99+7.2
③(+)×7+
④×153﹣0.6×53
⑤×+÷5+
⑥×[﹣(﹣)]
0.68+19.6= = 0.56÷0.4= 0.125×8=
12= 0.22×200= 100﹣0.86= =