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

Toán Lớp 6: B1: Tính nhanh a. 2/7 + -3/8 + 4/7 + -5/8 b. 1/2 + 2/3 + 3/4 + -4/5 + 5/6 + -6/7 + 7/8 + 6/7 + -5/6 + 4/5 + -3/4 + 2/3 + -1/2 c. 1/2

Tháng Mười Hai 5, 2022 Toán học 2 Comments 0 views

Toán Lớp 6: B1: Tính nhanh
a. 2/7 + -3/8 + 4/7 + -5/8
b. 1/2 + 2/3 + 3/4 + -4/5 + 5/6 + -6/7 + 7/8 + 6/7 + -5/6 + 4/5 + -3/4 + 2/3 + -1/2
c. 1/2 + -3/4 + 3/5 + 1/57 + -1/36 + 1/15 + -2/9
d. 1/2 + -1/5 + -5/7 + 1/6 + -3/35 + 1/3 + 1/41

Comments ( 2 )

  1. cattien
    cattien
    5 Tháng Mười Hai, 2022 at 9:37 chiều
    Reply
    a)
    2/7 + (-3)/8 + 4/7 + (-5)/8
    = 2/7 – 3/8 + 4/7 – 5/8
    = 6/7 – (3/8 + 5/8)
    = 6/7 – 1
    = -1/7
    b)
    1/2 + 2/3 + 3/4 + (-4)/5 + 5/6 + (-6)/7 + 7/8 + 6/7 + (-5)/6 + 4/5 + (-3)/4 + 2/3 + (-1)/2
    = 1/2 + 2/3 + 3/4 – 4/5 + 5/6 – 6/7 + 7/8 + 6/7 – 5/6 + 4/5 – 3/4 + 2/3 – 1/2
    = (1/2 – 1/2) + (2/3 + 2/3) + (3/4 – 3/4) – (4/5 – 4/5) + (5/6 – 5/6) – (6/7 – 6/7) + 7/8
    = 0 + 4/3 + 0 – 0 + 0 – 0 + 7/8
    = 4/3 + 7/8
    = (32 + 21)/24
    = 53/28
    c)
    1/2 + (-3)/4 + 3/5 + 1/57 + (-1)/36 + 1/15 + (-2)/9
    = 1/2 – 3/4 + 3/5 + 1/57 – 1/36 + 1/15 – 2/9
    = (1/2 + 3/5 + 1/15) – (3/4 + 1/36 + 2/9) + 1/57
    = 35/30 – 1 + 1/57
    = 1/6 + 1/57
    = 63/342
    d)
    1/2 + (-1)/5 + (-5)/7 + 1/6 + (-3)/35 + 1/3 + 1/41
    = (1/2 + 1/6 + 1/3) + ((-1)/5 + (-5)/7 + (-3)/35) + 1/41
    = 1 + (-1) + 1/41
    = 1/41

  2. doanthulan
    doanthulan
    5 Tháng Mười Hai, 2022 at 9:37 chiều
    Reply
    a, 3/7 + (-3/8) + 4/7 + (-5/8)   ( Câu này mình sửa lại đề cho dễ làm nhé ) 
    = ( 3/7 + 4/7 ) + ( -3/8 – 5/8 )
    = 1 + (-1)
    = 0 
    b, 1/2 + 2/3 + 3/4 + (-4/5) + 5/6 + (-6/7) + 7/8 + 6/7 + (-5/6) + 4/5 + (-3/4) + (-2/3) + (-1/2)
    = ( 1/2 – 1/2 ) + ( 2/3 – 2/3 ) + ( 3/4 – 3/4 ) + ( -4/5 + 4/5 ) + ( 5/6 – 5/6 ) + ( -6/7 + 6/7 ) + 7/8
    = 7/8
    c, 1/2 + (-3/4) + 3/5 + 1/57 + (-1/36) + 1/15 + (-2/9)
    = ( 1/2 – 3/4 – 1/36 – 2/9 ) + ( 3/5 + 1/15 ) + 1/57
    = ( 18/36 – 27/36 – 1/36 – 8/36 ) + ( 9/15 + 1/15 ) + 1/57
    = -1/2 + 2/3 + 1/57
    = 1/6 + 1/57
    = 7/38
    d, 1/2 + (-1/5) + (-5/7) + 1/6 + (-3/35) + 1/3 + 1/41
    = ( 1/2 + 1/6 + 1/3 ) + ( -1/5 – 5/7 – 3/35 ) + 1/41
    = ( 3/6 + 1/6 + 2/6 ) + ( -7/35 – 25/35 – 3/35 ) + 1/41
    = 1 + (-1) + 1/41
    = 1/41

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

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