一、计算。
  ① 1.3944÷0.84=                      ②0.225÷1.5×（4-3.68）                                    
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二、计算图形面积。
  

2、东西两城相距276千米,客车和货车同时从两城出发,3小时相遇,客车每小时行50千米,货车每小时行多少千米?                                                                                                             
分析:  要求货车每小时行多少千米?必需知道哪两个条件。
                                                                          
从已知条件可以推出：
                            
需品最后列综合算式：                            
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                           答：                       。