小学数学题求解,答案对就采纳求1/12,2/12,3/1,4/12……,239/12这239个数中所有不是整数的分数的和.3321/20 ÷41简便运算(-1/3+7/12-9/20+11/30-13/42+15/56)×21无过程不采纳,那些都是分数,过程也这样表达,
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![小学数学题求解,答案对就采纳求1/12,2/12,3/1,4/12……,239/12这239个数中所有不是整数的分数的和.3321/20 ÷41简便运算(-1/3+7/12-9/20+11/30-13/42+15/56)×21无过程不采纳,那些都是分数,过程也这样表达,](/uploads/image/z/2011758-6-8.jpg?t=%E5%B0%8F%E5%AD%A6%E6%95%B0%E5%AD%A6%E9%A2%98%E6%B1%82%E8%A7%A3%2C%E7%AD%94%E6%A1%88%E5%AF%B9%E5%B0%B1%E9%87%87%E7%BA%B3%E6%B1%821%2F12%2C2%2F12%2C3%2F1%2C4%2F12%E2%80%A6%E2%80%A6%2C239%2F12%E8%BF%99239%E4%B8%AA%E6%95%B0%E4%B8%AD%E6%89%80%E6%9C%89%E4%B8%8D%E6%98%AF%E6%95%B4%E6%95%B0%E7%9A%84%E5%88%86%E6%95%B0%E7%9A%84%E5%92%8C.3321%2F20+%C3%B741%E7%AE%80%E4%BE%BF%E8%BF%90%E7%AE%97%EF%BC%88-1%2F3%2B7%2F12-9%2F20%2B11%2F30-13%2F42%2B15%2F56%EF%BC%89%C3%9721%E6%97%A0%E8%BF%87%E7%A8%8B%E4%B8%8D%E9%87%87%E7%BA%B3%2C%E9%82%A3%E4%BA%9B%E9%83%BD%E6%98%AF%E5%88%86%E6%95%B0%2C%E8%BF%87%E7%A8%8B%E4%B9%9F%E8%BF%99%E6%A0%B7%E8%A1%A8%E8%BE%BE%2C)
小学数学题求解,答案对就采纳求1/12,2/12,3/1,4/12……,239/12这239个数中所有不是整数的分数的和.3321/20 ÷41简便运算(-1/3+7/12-9/20+11/30-13/42+15/56)×21无过程不采纳,那些都是分数,过程也这样表达,
小学数学题求解,答案对就采纳
求1/12,2/12,3/1,4/12……,239/12这239个数中所有不是整数的分数的和.
3321/20 ÷41简便运算
(-1/3+7/12-9/20+11/30-13/42+15/56)×21
无过程不采纳,那些都是分数,过程也这样表达,谢谢,答案对就采纳
小学数学题求解,答案对就采纳求1/12,2/12,3/1,4/12……,239/12这239个数中所有不是整数的分数的和.3321/20 ÷41简便运算(-1/3+7/12-9/20+11/30-13/42+15/56)×21无过程不采纳,那些都是分数,过程也这样表达,
首先239/12 < 20
于是 1/12 + 2/12+3/12+.239/12
= (1 +2+3.+239)/12 -(1+2+3.+19)
= ((1+239)X239)/(2X12) - ((19+1)X19)/2
=2390 - 190
=2200
2. 3321 /20 ÷ 41 =(3321 /41)/20= 81/20
3.(-1/3+7/12-9/20+11/30-13/42+15/56)×21
= -1/3+(3+4)/(3x4)-(4+5)/(4x5)+(5+6)/(5x6)-(6+7)/(6x7)+(7+8)/(7x8))×21
=(-1/3+(1/3+1/4)-(1/4+1/5)+(1/5+1/6)-(1/6+1/7)+(1/7+1/8))×21
=21/8
=2.625