(7.5-2.5)/(7.5+2.5)+2.4=5/10+2.4=0.5+2.4=2.9
(7.5+2.5)除(7.5-2.5)+2.4=10除5+2.4=2+2.4=4.4
(7.5+2.5)÷(7.5-2.5)+2.4=10÷5+2.4=2+2.4=4.4
(7.5+2.5)÷﹙7.5-2.5﹚+2.4=4.4