Réponse :
a. -7/50 + 2/75 = (-7X75)/(50X75) = -525/3750 = (5X15)/(5X750) = 15/750 = (3X5)/(3X250) = 5/250 = (1X5)/(50X5) = 1/50
b. 1/5 + -2/3 = (1X3)/(5X3) + (-2X5)/(3X5) = 3/15 + -10/15 = -7/15
c. 1/12 - 1/9 = (1X9)/(12X9) - (1X12)/(9X12) = 9/108 - 12/108 = -3/108 = (-1X3)/(36X3) = -1/36
d. 4/18 + 5/27 = (4X27/(18X27) + (5X18)/(27X18) = 108/286 + 90/286 = 198/286 = 99/143
Explications étape par étape
