Ta có: \(B=\frac{\frac19-\frac17-\frac{1}{11}}{\frac49-\frac47-\frac{4}{11}}+\frac{0,6-\frac{3}{25}-\frac{3}{125}-\frac{3}{625}}{\frac45-0,16-\frac{4}{125}-\frac{4}{625}}\)

\(=\frac{\frac19-\frac17-\frac{1}{11}}{4\left(\frac19-\frac17-\frac{1}{11}\right)}+\frac{\frac35-\frac{3}{25}-\frac{3}{125}-\frac{3}{625}}{\frac45-\frac{4}{25}-\frac{4}{125}-\frac{4}{625}}\)

\(=\frac14+\frac{3\left(\frac15-\frac{1}{25}-\frac{1}{125}-\frac{1}{625}\right)}{4\left(\frac15-\frac{1}{25}-\frac{1}{125}-\frac{1}{625}\right)}\)

\(=\frac14+\frac34=\frac44=1\)

A = 3+ 3/5+ 3/25+ 3/125+ 3/625

A = 3/1+ 3/5+ 3/25+ 3/125+ 3/625

A = 1875/625 + 375/625 + 75/625 + 15/625 + 3/625

A = 3 + 0,6 + 0,12 + 0,024 + 0,0048

A = 3,6 + 0,12 + 0,024 + 0,0048

A = 3,72 + 0,024 + 0,0048

A = 3,744 + 0,0048

A = 3,7488

       A =     3 + \(\dfrac{3}{5}\) + \(\dfrac{3}{25}\) + \(\dfrac{3}{125}\) + \(\dfrac{3}{625}\)

5\(\times\)A =   15 +  3 +   \(\dfrac{3}{5}\)  +  \(\dfrac{3}{25}\)  + \(\dfrac{3}{125}\)

5 \(\times\) A - A = 15 + 3 + \(\dfrac{3}{5}\) + \(\dfrac{3}{25}\) + \(\dfrac{3}{125}\) - (3 + \(\dfrac{3}{5}\) + \(\dfrac{3}{25}\) + \(\dfrac{3}{125}\) + \(\dfrac{3}{625}\))

4 \(\times\) A     = 15 + 3 + \(\dfrac{3}{5}\) + \(\dfrac{3}{25}\) + \(\dfrac{3}{125}\) - 3   - \(\dfrac{3}{5}\) - \(\dfrac{3}{25}\) - \(\dfrac{3}{125}\) - \(\dfrac{3}{165}\)

4  \(\times\) A =  (15 - \(\dfrac{3}{625}\)) + (3 - 3) + (\(\dfrac{3}{5}\) - \(\dfrac{3}{5}\)) + (\(\dfrac{3}{25}-\dfrac{3}{25}\)) + (\(\dfrac{3}{125}\)-\(\dfrac{3}{125}\))

4 \(\times\) A =   \(\dfrac{9372}{625}\)

       A = \(\dfrac{9372}{625}\) : 4

       A = \(\dfrac{2343}{625}\)

cho mẫu chung là 625 rồi tự quy đồng lên

  3 + 3/5 + 3/25 + 3/125 + 3/625

= 1875/625 + 375/625 + 75/625 + 15/625 + 3/625

= 2250/625 + 90/625 + 3/625

=     2340/625 + 3/625

=      2343/625

Bạn ơi đây là tính nhanh mà hic

sorry bạn rất nhìu

mong bạn thông cảm nếu sai mong bạn bỏ qua cho mình! :(

=3\(\div\)(1+5+125+625)

=3\(\div\)756

=\(\frac{1}{252}\)

3+3/5+3/25+3/125+3/625= 3/625x(625+125+25+5+1)= 3x781/625=2343/625

chu y: vi 3=3x625/625 

3/5=3x125/125x5=3x125/625

3/25=3x25/25x25=3x25/625

3/125=3x5/125x5=3x5/625

3/625=3x1/625

cộng các kết quả trên và đặt 3/625 làm nhân từ chúng ta có kết quả như trên.