Question

[PRO DZ]

Tính bằng cách thuận tiện nhất:

3/4x8/9x15/16x24/25x35/36

Answer 1

[Trần Ái Linh]

`3/4 xx  8/9 xx 15/16 xx 24/25 xx 35/36`

`= (3xx8xx15xx24xx35)/(4xx9xx16xx25xx36)`

`=(3xx4xx2xx5xx3xx4xx6xx7xx5)/(4xx3xx3xx4xx4xx5xx5xx6xx6)`

`=(2xx7)/(4xx6)`

`=(2xx7)/(2xx2xx6)`

`=7/12`

Answer 2

[_Jun(준)_]

\(\dfrac{3}{4}\times\dfrac{8}{9}\times\dfrac{15}{16}\times\dfrac{24}{25}\times\dfrac{35}{36}\)

= \(\dfrac{3\times8\times15\times24\times35}{4\times9\times16\times25\times36}\)

= \(\dfrac{3\times\left(2\times4\text{​​}\text{​​}\right)\times\left(3\times5\right)\times\left(6\times4\right)\times\left(5\times7\right)}{4\times\left(3\times3\right)\times\left(4\times4\right)\times\left(5\times5\right)\times\left(6\times6\right)}\)

=\(\dfrac{2\text{​​}\text{​​}\times3\times6\times\left(5\times7\right)}{3\times4\times5\times\left(6\times6\right)}\)

=\(\dfrac{\text{​​}\text{​​}7}{2\times6}\)= \(\dfrac{7}{12}\)