小升初数学简便计算解法1/3+1/15+1/35+1/63+1/99+1/143
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![小升初数学简便计算解法1/3+1/15+1/35+1/63+1/99+1/143](/uploads/image/z/10286000-8-0.jpg?t=%E5%B0%8F%E5%8D%87%E5%88%9D%E6%95%B0%E5%AD%A6%E7%AE%80%E4%BE%BF%E8%AE%A1%E7%AE%97%E8%A7%A3%E6%B3%951%2F3%2B1%2F15%2B1%2F35%2B1%2F63%2B1%2F99%2B1%2F143)
小升初数学简便计算解法1/3+1/15+1/35+1/63+1/99+1/143
小升初数学简便计算解法
1/3+1/15+1/35+1/63+1/99+1/143
小升初数学简便计算解法1/3+1/15+1/35+1/63+1/99+1/143
1/3+1/15+1/35+1/63+1/99+1/143
=1/1*3+1/3*5+1/5*7+1/7*9+1/9*11+1/11*13
=(1-1/3+1/3-1/5+1/5-1/7+1/7-1/9+1/9-1/11+1/11-1/13)/2
=(1-1/13)/2
=6/13
你好!
1/3+1/15+1/35+1/63+1/99+1/143
=(1-1/3)÷2+(1/3-1/5)÷2+(1/5-1/7)÷2+(1/7-1/9)÷2+(1/9-1/11)÷2+(1/11-1/13)÷2
=(1-1/3+1/3-1/5+1/5-1/7+1/7+1/9+1/9-1/11+1/11-1/13)÷2
=(1-1/13)÷2
=6/13
【希望可以帮到你】
拆项,合并。 上式=1/2X(1-1/3)+1/2X(1/3-1/5)+1/2X(1/5-1/7)+1/2X(1/7-1/9)+1/2X(1/9-1/11)+1/2X(1/111/13) =1/2X(1-1/3+1/3-1/5+1/5-1/7+1/7-1/9+1/9-1/11+1/11-1/13) =1/2X(1-1/13)=1/2X12/13=6/13
1/3+1/15+1/35+1/63+1/99+1/143
=1/2x(1-1/3)+1/2x(1/3-1/5)+.....1/2x(1/9-1/11)+1/2(1/11-1/13)
=1/2x(1-1/3+1/3-1/5+....+1/9-1/11+1/11-1/13)
=1/2x(1-1/13)
=1/2x12/13
=6/13