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222-9+11+12:2*14+14 = ? ( )

Toán Lớp 7: Tính: 50+$\frac{50}{3}$ +$\frac{25}{3}$ +$\frac{20}{4}$ +$\frac{10}{3}$ +$\frac{100}{6.7}$+-. +$\frac{100}{98.99}$+$\frac{1}{99}$

Toán Lớp 7: Tính:
50+$\frac{50}{3}$ +$\frac{25}{3}$ +$\frac{20}{4}$ +$\frac{10}{3}$ +$\frac{100}{6.7}$+….. +$\frac{100}{98.99}$+$\frac{1}{99}$

Comments ( 2 )

  1. Giải đáp:
    A=99 
    Lời giải và giải thích chi tiết:
     Đặt A=50+{50}/3+{25}/3+{20}/4+{10}/3+{100}/{6.7}+…+{100}/{98.99}+1/{99}
    A=(50+{50}/3+{25}/3+{20}/4+{10}/3)+({100}/{6.7}+…+{100}/{98.99}+1/{99})
    A=100(1/{1.2}+1/{2.3}+1/{3.4}+1/{4.5}+1/{5.6})+100(1/{6.7}+1/{7.8}+…+1/{99.100})
    A=100(1/{1.2}+1/{2.3}+1/{3.4}+…+1/{99.100})
    A=100(1-1/{100})
    A=100-{100}/{100}
    A=100-1=99

  2. 50 + 50/3 + 25/3 + 20/4 + 10/3 + 100/6.7 + … + 100/98.99 + 1/99
    = (50 + 50/3 + 25/3 + 20/4 + 10/3) + ( 100/6.7 + … + 100/98.99 + 100/99.100)
    = (100/1.2 + 100/2.3 + 100/3.4 + 100/4.5 + 100/5.6) + 100.(1/6.7 + … + 1/98.99 + 1/99.100)
    = 100(1/1.2 + 1/2.3 + 1/3.4 + 1/4.5 + 1/5.6) + 100 . (1/6 – 1/7 + … + 1/98 – 1/99 + 1/99 – 1/100)
    = 100(1/1 – 1/2 + 1/2 – 1/3 + 1/3 – 1/4 + 1/4 – 1/5 + 1/5 – 1/6) + 100.(1/6 – 1/100)
    = 100(1 – 1/6) + 100 . 47/300
    = 100 . 5/6 + 100 . 47/300
    = 100 . (5/6 + 47/300)
    = 100 . 99/100
    = 99
     

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222-9+11+12:2*14+14 = ? ( )