Ex 4
15 ari+2.23 hm patrati-640 m patrati=15+223-6.4=231.6 dam patrati
15 ari=15 dam patrati
2.23 hm patrati=223 dam patrati
640 m patrati=6.4 dam patrati
Ex 5
Ma=a+b+c:3=4.5
Ma=a+b:2=3.5
a+b=3.5*2=7
(7+c):3=4.5
7+c=4.5*3
7+c=13.5
c=13.5-7=6.5 acesta este numarul care trebuia aflat