题目

       Men have traveled ever since they first appeared on the earth.        Long ago, they did not travel for pleasure but to find new places where their cattle could feed, or to        from their enemies, or to find more favorable climates.        They traveled on foot. Their journeys were long, tiring, and often dangerous. They protected themselves with simple weapons（武器）, such as wooden sticks or stone clubs, and by lighting fires at night and, adove all, keeping together.        Very soon they discovered easier ways of traveling. They rode on the bac 用竖式计算。 （1）427×3 （2）729÷6 （3）424÷3 （4）826÷6