chịu mình không thể giải được

Mấy con gà lắt nhắt này, dễ thế mà cũng ko tính đc.

chịu dài thế ai mà tính đc

Chọn A

\(\dfrac{3}{8}+\dfrac{1}{4}=\dfrac{3}{8}+\dfrac{2}{8}=\dfrac{5}{8}\) 
=> Chọn A

A

A)6 và 4/5-(1 và 2/3+3 và 4/5)

=6+4/5-1-2/3-3-4/5

=(6-1-3)+(4/5-4/5)-2/3

=2-2/3=1 và 1/3

B)[(19+5/8/7/12)-(13+1/4/7/12)]X4/5

=[(19-13)+(5/8/7/12-1/4/7/12)]X4/5

=[6+3/8/7/12]X4/5

=[6+9/14]X4/5

=93/14 X4/5=186/35

nhớ

AI GIÚP MÌNH VỚI MÌNH ĐANG CẦN GẤP

1/3+1/6+1/12+1/24=8/24+4/24+2/24+1/24=15/24=5/8

tk cho mk nha!

\(\frac{1}{3}+\frac{1}{6}+\frac{1}{12}+\frac{1}{24}=\frac{8}{24}+\frac{4}{24}+\frac{2}{24}+\frac{1}{24}=\frac{15}{24}=\frac{5}{8}\)

\(\frac{5}{8}\)

~Hok tốt~

\(a.32,5-3\cdot0,87=32,5-2,61=29,89\)

\(8,5\cdot\left(1\dfrac{1}{2}+\dfrac{4}{4}\right):5=8,5\cdot\left(\dfrac{3}{2}+\dfrac{4}{4}\right):5\\ =8,5\cdot\left(\dfrac{6}{4}+\dfrac{4}{4}\right):5\\ =8,5\cdot\dfrac{10}{4}:5\\ =\dfrac{85}{4}:5\\ =\dfrac{17}{4}\)

\(b.30,96-6,45+14,4:3=30,96-6,45+4,8\\ =29,31\)

\(\dfrac{2}{5}\cdot\left(\dfrac{4}{5}-\dfrac{1}{2}\right)=\dfrac{2}{5}\cdot\left(\dfrac{8}{10}-\dfrac{5}{10}\right)\\ =\dfrac{2}{5}\cdot\dfrac{3}{10}=\dfrac{3}{25}\)

bài 2

\(a.2,5\cdot12,5\cdot8\cdot0,4=\left(2,5\cdot0,4\right)\left(12,5\cdot8\right)\\ =1\cdot100=100\)

b,\(\dfrac{12}{15}\cdot\dfrac{5}{6}\cdot\dfrac{3}{20}\cdot\dfrac{32}{5}=\dfrac{12\cdot5\cdot3\cdot32}{15\cdot6\cdot20\cdot5}\\ =\dfrac{3\cdot4\cdot5\cdot3\cdot4\cdot8}{3\cdot5\cdot2\cdot3\cdot5\cdot4\cdot5}=\dfrac{16}{25}\)

Bài 1: 

a) \(32.5-3\cdot0.87=32.5-2.61=29.89\)

\(8.5\cdot\left(1\dfrac{1}{2}+\dfrac{4}{4}\right):5=8.5\cdot\dfrac{5}{2}:5=\dfrac{17}{2}\cdot\dfrac{5}{2}:5=\dfrac{85}{4}\cdot\dfrac{1}{5}=\dfrac{17}{4}\)

b) \(30.96-6.45+14.4:3=24.51+4.8=29.33\)

\(\dfrac{2}{5}\left(\dfrac{4}{5}-\dfrac{1}{2}\right)=\dfrac{2}{5}\left(\dfrac{8}{10}-\dfrac{5}{10}\right)=\dfrac{2}{5}\cdot\dfrac{3}{10}=\dfrac{6}{50}=\dfrac{3}{25}\)

\(\frac{1}{3}+\frac{1}{4}+\frac{1}{5}+\frac{4}{6}+\frac{9}{12}+\frac{16}{20}\)

\(=\frac{1}{3}+\frac{1}{4}+\frac{1}{5}+\frac{2}{3}+\frac{3}{4}+\frac{4}{5}\)

\(=\left(\frac{1}{3}+\frac{2}{3}\right)+\left(\frac{1}{4}+\frac{3}{4}\right)+\left(\frac{1}{5}+\frac{4}{5}\right)\)

\(=\frac{3}{3}+\frac{4}{4}+\frac{5}{5}\)

\(=1+1+1\)

\(=3\)

\(\dfrac{1}{3}+\dfrac{1}{4}+\dfrac{1}{5}+\dfrac{4}{6}+\dfrac{9}{12}+\dfrac{16}{20}\)

\(=\dfrac{1}{3}+\dfrac{1}{4}+\dfrac{1}{5}+\dfrac{2}{3}+\dfrac{3}{4}+\dfrac{4}{5}\)

\(=\left(\dfrac{1}{3}+\dfrac{2}{3}\right)+\left(\dfrac{1}{4}+\dfrac{3}{4}\right)+\left(\dfrac{1}{5}+\dfrac{4}{5}\right)\)

\(=\dfrac{3}{3}+\dfrac{4}{4}+\dfrac{5}{5}\)

\(=1+1+1=3\)

12 phần 25 trừ cho 14 phần 5 bằng bao nhiêu

8==D LOL

d: =214

\(a,\dfrac{5}{6}+\dfrac{7}{12}=\dfrac{10}{12}+\dfrac{7}{12}=\dfrac{17}{12}\\ b,\dfrac{3}{4}\times\dfrac{2}{5}=\dfrac{6}{20}=\dfrac{3}{10}\\ c,51462\times6308=324622296\\ d,9630:45=214\)