①3.5×+5.5×80%+0.8
②(9.88+0.24÷2)×7.6
③36÷[1-()]
④
⑤12.38+5.76-2.38+4.24
12÷0.9≈
12÷0.03=
25×40%=
2.4-2.4×0.5=
8×5÷8×5=
x+7%x=5.35 (1-60%)x=5.6
3.9x÷(1+30%)=50 3x+60%x=12
48-25%x=32 4%x-6=0.4