Răspuns :
11 supra 15 +7 supra 15 - 8 supra 15 = 10 supra 15
11 supra 15+ 7 supra 15 =18 supra 15
18 supra 15 - 8 supra 15 =10 supra 15
11/15 + 7/15 - 8/15
[tex]\it \dfrac{11}{15}+\dfrac{7}{15}-\dfrac{8}{15}=\dfrac{11+7-8}{15}=\dfrac{\ 10^{(5}}{15}=\dfrac{2}{3}[/tex]