\(\frac{7}{13}×\frac{5}{14}×\frac{39}{15}\)
\(=\frac{7×5×39}{13×14×15}\)
\(=\frac{7×5×13×3}{13×7×2×5×3}\)
\(=\frac{1}{2}\)
\(\frac{7}{13}×\frac{5}{14}×\frac{39}{15}\)
\(=\frac{7×5×39}{13×14×15}\)
\(=\frac{7×5×3×13}{13×2×7×3×5}\)
\(=\frac{1}{2}\)
7/13*5/14*39/15
= 7 x 5 x 39 / 13 x 14 x 15
= 7 x 5 x 3 x 13 / 13 x 2 x 7 x 3 x 5
Bước nháp : 7 x 5 x 3 x 13 / 13 x 2 x 7 x 3 x 5 ( không viết vào bài :))
= 5 / 10 = 1/2
\(\frac{7}{13}\times\frac{5}{14}\times\frac{39}{15}\)
\(=\frac{7\times5\times13\times3}{13\times7\times2\times5\times3}=\frac{1}{2}\)
