c):
${ \dfrac{3 × 4 × 7}{12 × 8 × 9}}$
`=` ${ \dfrac{7}{8 × 9}}$
`= 7/72`
d):
${ \dfrac{4 × 5 × 6}{12 × 10 × 8}}$
`= 120/960`
`= 1/8`
e):
`12/25 + 3/5 + 13/25`
`= (12/25 + 13/25) + 3/5`
`= 25/25 + 3/5`
`= 1 + 3/5`
`= 8/5`
f):
`3/2 + 2/3 + 4/3`
`= (2/3 + 4/3) + 3/2`
`= 6/3 + 3/2`
`= 2/1 + 3/2`
`= 2 + 3/2`
`= 7/2`
Cho mình xin hay nhất nha bạn!!!!
@Drew Mclntyre
