bonjour
( 3 - 2/3) : ( 4/3 x 7 )
= ( 9/3 - 2 /3) : ( 28/3)
= 7/3 x 3 /28
= 21/84 = 1/4
( 2/3 : 5 /6) - 2/5
= ( 4/6 - 5 /6) - 2 /5
= - 1/6 - 2 /5
= - 5/30 - 12/30
= - 17/30
( - 3/4 + 1 /2) : ( 2/5 - 5 /2 )
= ( - 3/4 + 2/4) : ( 4/10 - 25/10)
= - 1/4 x - 10 /21
= 10/84
= 5/42
