2/7 + 1/5 + 5/7 + 4/5
tính bằng cách thuận tiện nhất
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
\(2\times5\times\dfrac{11}{3}\times11\times5=\left(2\times5\times5\right)\times\left(\dfrac{11}{3}\times11\right)=50\times\dfrac{121}{3}=\dfrac{6050}{3}\)
2 x 5 x 11/3 x 11 x 5
= 10 x 11/3 x 11 x 5
= ( 10 x 5 ) x( 11/3 x 11)
= 50 x 121/3
= 6050/3
\(\dfrac{2}{7}\times\dfrac{1}{5}+0,2\times\dfrac{4}{7}\)
\(=\dfrac{2}{7}\times\dfrac{1}{5}+\dfrac{1}{5}\times\dfrac{4}{7}\)
\(=\dfrac{1}{5}\times\left(\dfrac{2}{7}+\dfrac{4}{7}\right)\)
\(=\dfrac{1}{5}\times\dfrac{6}{7}\)
\(=\dfrac{6}{35}\)
\(\left(\dfrac{2}{7}+\dfrac{5}{7}\right)+\left(\dfrac{3}{5}+\dfrac{2}{5}\right)+\left(\dfrac{3}{8}+\dfrac{4}{8}+\dfrac{1}{8}\right)+\left(\dfrac{1}{9}+\dfrac{8}{9}\right)=1+1+1+1=4\)
`2/5 xx 4/7 + 3/5 xx 4/7`
`= 4/7 xx (2/5 + 3/5)`
`= 4/7 xx 1`
`= 4/7`
\(5\dfrac{3}{4}:3+2\dfrac{1}{4}\times\dfrac{1}{3}-\dfrac{1}{8}=\left(5\dfrac{3}{4}+2\dfrac{1}{4}\right)\times\dfrac{1}{3}-\dfrac{1}{8}\\ =8\times\dfrac{1}{3}-\dfrac{1}{8}=\dfrac{8}{3}-\dfrac{1}{8}=\dfrac{61}{24}\\ ----\\ \dfrac{3}{5}:\dfrac{5}{6}:\dfrac{6}{7}:\dfrac{7}{8}+\dfrac{2}{5}+\dfrac{23}{35}\\ =\dfrac{3}{5}\times\dfrac{6}{5}\times\dfrac{7}{6}\times\dfrac{8}{7}+\dfrac{2}{5}+\dfrac{23}{35}=\dfrac{18}{25}\times\dfrac{4}{3}+\dfrac{2}{5}+\dfrac{23}{35}=\dfrac{353}{175}\)
= 2/7+5/7+1/5+4/5
=7/7+5/5
=1+1
=2
= (2/7+5/7)+(1/5+4/5)
=1+1=2