Răspuns :
2*30=60; 60*1=60;
2*2*15=60; 2*1*30=60;
2*(15+15)=60; 2*(29+1)=60;
(31-1)*2=60; (40-10)*2=60.
2*2*15=60; 2*1*30=60;
2*(15+15)=60; 2*(29+1)=60;
(31-1)*2=60; (40-10)*2=60.