1414+1515+1616+1717+1818+1919/2020+2121+2222+2323+2424+2525=2525 nhé bạn

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

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

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

\(A=\frac{1}{2}×1\)

\(A=\frac{1}{2}\)

\(B=\frac{1212}{2121}×\frac{151515}{161616}\)

\(B=\frac{1212:101}{2121:101}×\frac{151515:10101}{161616:10101}\)

\(B=\frac{12}{21}×\frac{15}{16}\)

\(B=\frac{12×15}{21×16}\)

\(B=\frac{3×4×3×5}{3×7×4×4}\)

\(B=\frac{15}{28}\)

a)\(\frac{1}{2}:\frac{1}{5}+\frac{1}{3}:\frac{1}{5}+\frac{1}{6}:\frac{1}{5}\)

=\(\left(\frac{1}{2}+\frac{1}{3}+\frac{1}{6}\right):\frac{1}{5}\)

=\(1:\frac{1}{5}\)

=5

b)\(\frac{1515\text{×}161616}{151515\text{×}1616}\)

=1

\(\frac{1414+1515+1616+1717+1818+1919}{2020+2121+2222+2323+2424+2525}\)

\(=\frac{101\times\left(14+15+16+17+18+19\right)}{101\times\left(20+21+22+23+24+25\right)}\)

\(=\frac{14+15+16+17+18+19}{20+21+22+23+24+25}\)

+) Tử số :

Số các số hạng là : ( 19 - 14 ) : 1 + 1 = 6 ( số )

Tổng là : ( 19 + 14 ) x 6 : 2 = 99

+) Mẫu số :

Số các số hạng là : ( 25 - 20 ) : 1 + 1 = 6 ( số )

Tổng là : ( 25 + 20 ) x 6 : 2 = 135

\(\Leftrightarrow\frac{99}{135}=\frac{11}{15}\)

\(\frac{1414+1515+1616+1717+1818+1919}{2020+2121+2222+2323+2424+2525}\)

= \(\frac{\left(1414+1919\right)+\left(1515+1818\right)+\left(1616+1717\right)}{\left(2020+2525\right)+\left(2121+2424\right)+\left(2222+2323\right)}\)

= \(\frac{3333+3333+3333}{4545+4545+4545}=\frac{3333}{4545}=\frac{11}{15}\)

t i c k nhé!! 45435436457

11/15

11/15

Ta có:So sánh \(\frac{161616}{242424}và\frac{2}{3}\)

\(\frac{161616}{242424}=\frac{16X10101}{24X10101}=\frac{16}{24}=\frac{2X8}{3X8}=\frac{2}{3}\)

Vì \(\frac{2}{3}=\frac{2}{3}\)

Nên \(\frac{161616}{242424}=\frac{2}{3}\)

Ta có \(\frac{161616}{242424}=\frac{161616:80808}{242424:80808}=\frac{2}{3}\)

=> \(\frac{161616}{242424}=\frac{2}{3}\)

Dau > nha!

theo mình là điền dấu =