27. Se consideră numerele a=-9 și b= +4 Calculati: a) a-b;
b)|a-b-(-13);
c) |al-161;
d) -a-b+|-20;
e) (-a)-(+b)+(-15);
f) \a-b1-4-2.​

Acurious child asked his mother: “mommy, why are some of your hairs turning grey? ” the mother tried to use this occasion to teach her child: “it is because of you, dear. every bad action of yours will turn one of my hairs grey! ” the child replied innocently: “now i know why grandmother has only grey hairs on her head.”