一个数列24个数,unit digit都为5,1/3的tenth为0, 1/3的tenth为2, 1/3的tenth为4.问sum的tenth是几 我好像选的2 思路:在新发的帖子中发现了这道题,那个楼主的描述是把所有tenth都换成tens。。。这样就对啦~单纯的十位数相加:为0*8+2*8+4*8 十位数是8, 24个个位上的5相加十位是2,所以答案就是0 最简单的方法,因为题目只涉及到后两位,我们可以假设这些数字是8个5,8个25,8个45,相加得到600~so,problem solved~ 问的不是sum tenth么...那不就是8么.. All 24 numbers have the number 5 at the one digit. Eight of them have 0 at the ten digit. Another eight have 2 at the ten digit. Still another have 4 at the digit. Therefore, if you ONLY as the ten and one digits of the 24 numbers together, you add 8 numbers of (05), 8 numbers of (45), and 8 numbers of (25). This sum = 8*(5 + 45 + 25) = 8*75 = 600. Therefore, the numbe on the ten digit of the sum is 0. -- by 会员 sdcar2010 (2010/12/27 22:06:24)
What I want to argue is "ten" do not means "tenth" ? is that the reason that i am wrong? |