Write out the answer. 這是一道應(yīng)用題，請列式解答，并寫出答語。
       Three cats are hungry. The yellow cat wants to eat twenty-one little fish. The white cat wants to eat twenty
little fish. The black cat wants to eat thirty-one little fish. How much fish do they want to eat?
1. 列式解答：                                    
2. 寫出答語：                                    

參考答案：
1. 21+20+31=72
2. They want to eat seventy fish.

Write out the answer. 這是一道應(yīng)用題，請列式解答，并寫出答語。
       Three cats are hungry. The yellow cat wants to eat twenty-one little fish. The white cat wants to eat twenty
little fish. The black cat wants to eat thirty-one little fish. How much fish do they want to eat?
1. 列式解答：                                    
2. 寫出答語：                                    

參考答案：
1. 21+20+31=72
2. They want to eat seventy fish.