Question

3/7 + 4/15 + -8/21 + -0,4

cẦn gấp hứa k

Answer 1

=9/21-8/21+4/15-6/15

=1/21-2/15

=-3/35

Answer 2

`3/7+4/15+(-8/21) +(-0,4)`

`=3/7+4/15 - 8/21 - 0,4`

`=3/7+4/15 - 8/21 - 2/5`

`=(3/7-8/21)+(4/15-2/5)`

`= (9/21-8/21)+ (4/15 - 6/15)`

`= 1/21 + (-2/15)`

`=1/21-2/15`

`=-3/35`