Bonsoir,

a. Calculer

14-(+17)= 14-17= -3

14+(-7)= 14+(-7)= 14-7=7

14-(-17)= 14+17= + .. calcule

14+(7)=14+7= + ... calcule

14+5-12= 19-12= + ... calcule

14+5+12= 19+12= + ... calcule

14-5+12= 9+12= + ... calcule

b. je supprime les parenthèses

14+(5-12) -> 14+5-12

14-(5+12) -> 14-5-12

14-(-5-12) -> 14+5-12