299×101                               2+3﹣3+1+1                   
24.6×4.6+246×0.44+24.6                ×27+16×                        
9900÷25÷4                            ×98+×2                            
11﹣﹣（×+×）            +4﹣（+）                        
1999+999×999                           20.07×1994﹣19.93×2007                
0.125×32×2.5                            2002×
12﹣2×3÷2                        0.65×6.4﹣6.5×0.54+65×9%
9999+999+99+9+4                  ×98+2÷
×8+×3﹣                         35×+35×+35×
2.25×1.8+17.5×0.18                    （++）÷．