rendresles calculs suivants en fraction irreductible 9/2 +4/5 X (10/16) = 13/7 moins ( 4/3 +11/21) =

= 9 / 2 + 4 / 5 x 10 / 16
= 9 / 2 + 40 / 80
= 9 / 2 + 1 / 2
= 10 / 2
= 5

= 13 / 7 - ( 4 / 3 + 11 / 21 )
= 13 / 7 - ( 28 / 21 + 11 / 21 )
= 13 / 7 - 39 / 21
= 39 / 21 - 39 / 21
= 0