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

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

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

\(A=\frac{1}{2}×1\)

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

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

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

\(B=\frac{12}{21}×\frac{15}{16}\)

\(B=\frac{12×15}{21×16}\)

\(B=\frac{3×4×3×5}{3×7×4×4}\)

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

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

151515/212121=5/7

66666/77777=6/7

Vậy 5/7+ 6/7 =11/7

Tk mình đi mọi người mình bị âm nè!

Ai tk mình mình tk lại cho!

a) 15/3 x 7/5 + 7/5 x 10/3 + 7/5

= (15/3 + 10/3  + 1) x 7/5

= 28/3 x 7/5

= 196/15

c) 2009 + 3567 + 6433 - 1009

= (2009 - 1009 ) + (3567 + 6433)

= 1000 + 10000

= 11000

\(\frac{15}{3}\)x\(\frac{7}{5}+\frac{7}{5}\)x\(\frac{10}{3}+\frac{7}{5}\)

= \(\frac{15}{3}\)x \(\frac{7}{5}+\frac{7}{5}\)x \(\frac{10}{3}+\frac{7}{5}x1\)

=\(\left(\frac{15}{3}+\frac{10}{3}+1\right)\)x \(\frac{7}{5}\)

= \(\frac{100}{3}\)x \(\frac{7}{5}\)

=\(\frac{140}{3}\)

\(\frac{1212}{1717}\)x \(\frac{165165}{132132}\)x\(\frac{515151}{515151}\)

= \(\frac{12}{17}\)x \(\frac{165}{132}\)x \(\frac{51}{51}\)

= \(\frac{12}{17}\)x\(\frac{165}{132}\)x 1

= \(\frac{165}{187}\)

2009 + 3567 + 6433 - 1009

= ( 2009 - 1009 ) + (3567 +6433 )

=1000 + 10000

= 11000

=18000

giải thích rõ ra