A=-7/9+5/8+7/9+-3/8 B=-2/7.5/9+-5/7.5/9+1/3 C=12/11_(1/11-2/9) D=7/15.3/14:13/20

`A = -7/9 + 5/8 + 7/9 + -3/8`

`A = ( -7/9 + 7/9 ) + ( 5/8 + -3/8 )`

`A = 0 + 1/4`

`A = 1/4`

_____________________

`B = -2/7 . 5/9 + -5/7 . 5/9 + 1/3`

`B = [ 5/9 . ( -2/7 + -5/7 ) ] + 1/3`

`B = [ 5/9 . (-1) ] + 1/3`

`B = -5/9 + 1/3`

`B = -2/9`

_____________________

`C = 12/11 - ( 1/11 - 2/9 )`

`C = 12/11 - 1/11 + 2/9`

`C = 1 + 2/9`

`C = 11/9`

_____________________

`D = 7/15 . 3/14 : 13/20`

`D = 7/15 . 3/14 . 20/13`

`D = 1/10 . 20/13`

`D = 2/13`

$\\$

`#Yume``e`