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

Toán Lớp 7: Tính nhanh 1/2+5/6+11/12+19/20+29/30+41/42+55/56+71/72+89/90

Tháng Hai 13, 2023 Toán học 2 Comments 0 views

Toán Lớp 7: Tính nhanh
1/2+5/6+11/12+19/20+29/30+41/42+55/56+71/72+89/90

Comments ( 2 )

  1. dongoctuan
    dongoctuan
    13 Tháng Hai, 2023 at 7:17 chiều
    Reply
    Lời giải và giải thích chi tiết:
    1/2+5/6+11/12+19/20+29/30+41/42+55/56+71/72+89/90
    =1-1/2+1-1/6+1-1/12+1-1/20+1-1/30+1-1/42+1-1/56+1-1/72+1-1/90
    =9-(1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90)
    =9-[1/(1/2)+1/(2×3)+1/(3×4)+1/(4×5)+1/(5×6)+1/(6×7)+1/(7×8)+1/(8×9)+1/(9×10)]
    =9-(1-1/2+1/2+1/3-1/3+1/4-1/4+1/5-1/5+1/6-1/6-1/7+1/7-1/8+1/8-1/9+1/9-1/10)
    =9-(1-1/10)
    =9-9/10
    =81/10
            Gửi bạn!!!

  2. ngoclandiep
    ngoclandiep
    13 Tháng Hai, 2023 at 7:17 chiều
    Reply
    Giải đáp:
    81/10
    Giải thích các bước:
    1/2+5/6+11/12+19/20+ 29/30 + 41/42 + 55/56 + 71/72 + 89/90
    = 1 – 1/2 + 1 – 1/6 + 1 – 1/12 + 1 – 1/20 + 1 – 1/30 + 1 – 1/42 + 1 – 56 + 1 – 1/72 + 1 – 1/90
    = 9 – ( 1/2 + 1/6 + 1/12 + 1/20 + 1/30 + 1/42 + 1/56 + 1/72 + 1/90 )
    = 9 – ( 1/1.2 + 1/2.3 + 1/3.4 + 1/4.5 + 1/5.6 + 1/6.7 + 1/7.8 + 1/8.9 + 1/9.10 )
    = 9 – ( 1 – 1/2 + 1/2 – 1/3 + 1/3- 1/4 + 1/4 – 1/5 + 1/5 – 1/6 + 1/6 – 1/7 + 1/7 – 1/8 + 1/8 – 1/9 + 1/9 – 1/10 )
    = 9 – 9/10
    = 81/10
    Honkers

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

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