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

Toán Lớp 7: Tính E = 10,11 + 11,12 + 12,13 + …+ 98,99 + 99,10

Toán Lớp 7: Tính E = 10,11 + 11,12 + 12,13 + …+ 98,99 + 99,10

Comments ( 2 )

  1. E = 10,11 + 11,12 + 12,13 + …+ 98,99 + 99,10

    toan-lop-7-tinh-e-10-11-11-12-12-13-98-99-99-10

  2. Ta có :
    E=10.11 +11.12 +12.13+…+98,99+99.10
    ⇒E=10+11/100+11+12/100+12+13/100+…+98+99/100+99+10/100
    ⇒E= (10+11+12+…+99) + [(10+11+12+…+99)/100]
    Lại có 10+11+12+…+99= (99+10)×[(99-10)÷1+1]÷2=109×90÷2=4905
    ⇒E=4905+4905/100=4905+49.05=4954,05
    Chúc bạn học tốt nhé????????????!
     

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