题干

(1)求满足下列条件的最小自然数,使得它的平方的前两位是20;

(2)求满足下列条件的最小自然数,使得它的平方的后两位是04;

(3)求满足下列条件的最小自然数,使得它的平方的前两位是20,后两位是04.

上一题 下一题 0.0难度 选择题 更新时间:2017-07-07 02:28:04

答案(点此获取答案解析)

解:(1)因为14×14=196,15×15=225,因此,平方的前两位是20的三位数不存在;

那么再看平方的前两位是20的四位数,前两位是20的四位数最小是45×45=2025,因此最小数是45.

(2)平方最后一位是4的,只有2×2或8×8,但通过试探,只有48×48=2304,符合最小数.

(3)448×448=200704,最小数是448.

同类题5

阅读理解

       There is a very instructive incident involving the life of Alexander, the great Greek king. Alexander, after conquering many kingdoms, was returning home. On the way, he fell ill and it took him to his death bed. With death staring him in his face, Alexander realized how his conquests, his great army, his sharp sword and all his wealth were of no consequence. So, he lay helplessly waiting to breathe his last. He called his generals and said, “I will depart from this world soon, I have three wishes, please carry them out without fail.”

    “My first desire is that,” said Alexander, “My physicians alone must carry my coffin.” After a pause, he continued, “Secondly, I desire that when my coffin is being carried to the grave, the path leading to the graveyard be strewn(撒满) with gold, silver and precious stones which I have collected.” The king continued, “My third and last wish is that both my hands be kept hanging out of my coffin.” Alexander's favorite general kissed his hand and pressed them to his heart. “Oh King, we assure you that your wishes will all be fulfilled. But tell us why do you make such strange wishes?”

     At this Alexander took a deep breath and said, “I would like the world to know of the three lessons I have just learnt. I want my physicians to carry my coffin because people should realize that no doctor can really cure any body. They are powerless and cannot save a person from the clutches of death. So let people not take life for granted.

      The second wish of strewing gold, silver and other riches on the way to the graveyard is to tell people that not even a bit of gold will come with me. I spent all my life earning riches but cannot take anything with me. Let people realize that it is just a waste of time to chase wealth.

       And about my third wish of having my hands hanging out of the coffin, I wish people to know that I came empty-handed into this world and empty-handed I go out of this world.” With these words, the king closed his eyes. Soon he let death conquer him and breathed his last.