Register Now

Login

Lost Password

Lost your password? Please enter your email address. You will receive a link and will create a new password via email.

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 + 3/2 + 3/4 + -4/5 + 5/6 + -6/7 + 7/8 + 6/7 + -5/6 + 4/5 + -3/4 + 2/3 + -1/2 c. 1/

Tháng Mười Hai 4, 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 + 3/2 + 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 + -1/56 + 1/15 + -2/9
d. 1/2 + -1/5 + -5/7 + 1/6 + -3/35 + 1/3 + 1/41

Comments ( 2 )

  1. dongoclandiem
    dongoclandiem
    4 Tháng Mười Hai, 2022 at 12:41 sáng
    Reply
    Lời giải và giải thích chi tiết:
    $\textit{#laviken#}$
    a)$\dfrac{2}{7}$ + $\dfrac{-3}{8}$ + $\dfrac{4}{7}$ + $\dfrac{-5}{8}$
    = ($\dfrac{2}{7}$ + $\dfrac{4}{7}$) + ($\dfrac{-3}{8}$ + $\dfrac{-5}{8}$)
    =$\dfrac{6}{7}$ + $\dfrac{-8}{8}$
    =$\dfrac{6}{7}$ – 1
    =$\dfrac{-1}{7}$ 
    b)$\dfrac{1}{2}$ + $\dfrac{2}{3}$ + $\dfrac{3}{4}$ + $\dfrac{-4}{5}$+$\dfrac{5}{6}$ + $\dfrac{-6}{7}$ + $\dfrac{7}{8}$ + $\dfrac{6}{7}$ + $\dfrac{-5}{6}$ + $\dfrac{4}{5}$ + $\dfrac{-3}{4}$ + $\dfrac{2}{3}$+$\dfrac{-1}{2}$ 
    = ($\dfrac{1}{2}$ + $\dfrac{-1}{2}$) + ($\dfrac{2}{3}$ + $\dfrac{2}{3}$)+$\dfrac({3}{4}$ + $\dfrac{-3}{4}$) + ($\dfrac{-4}{5}$ + $\dfrac{4}{5}$) + ($\dfrac{-5}{6}$ + $\dfrac{5}{6}$) + ($\dfrac{-6}{7}$ + $\dfrac{6}{7}$)+$\dfrac{7}{8}$
    = $\dfrac{4}{3}$ + $\dfrac{7}{8}$
    =$\dfrac{32}{24}$ + $\dfrac{21}{24}$
    =$\dfrac{53}{28}$
    c)$\dfrac{1}{2}$ + $\dfrac{-3}{4}$ + $\dfrac{3}{5}$) + $\dfrac{1}{57}$ + $\dfrac{-1}{56}$ + $\dfrac{1}{15}$ + $\dfrac{-2}{9}$ 
    =($\dfrac{1}{2}$ + $\dfrac{3}{5}$) + $\dfrac{1}{15}$+ ($\dfrac{-2}{9}$ + $\dfrac{-3}{4}$ + $\dfrac{-1}{56}$ + $\dfrac{1}{57}$ 
    = $\dfrac{35}{30}$ +(-1) + $\dfrac{1}{57}$
    =$\dfrac{7}{6}$ +(-1) + $\dfrac{1}{57}$
    =$\dfrac{1}{6}$ + $\dfrac{1}{57}$
    =$\dfrac{63}{342}$ 
    d)$\dfrac{1}{2}$ + $\dfrac{-1}{5}$ + $\dfrac{-5}{7}$) + $\dfrac{1}{6}$ + $\dfrac{-3}{35}$ + $\dfrac{1}{3}$ + $\dfrac{1}{41}$ 
    =($\dfrac{1}{2}$ + $\dfrac{1}{3}$ + $\dfrac{1}{6}$) + ($\dfrac{1}{5}$ + $\dfrac{-5}{7}$ + $\dfrac{-3}{35}$) + $\dfrac{1}{41}$ 
    =1 + (-1) + $\dfrac{1}{41}$ 
    =$\dfrac{1}{41}$ 
     ~ Chúc bạn học tốt ~
     

  2. huongtructram
    huongtructram
    4 Tháng Mười Hai, 2022 at 12:40 sáng
    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

Leave a reply

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

Thanh Thu

About Thanh Thu