Răspuns :
(8X9+S-5X8)-(30-5X2+5)=100:2:2
(72+S-40)-(30-10+5)=25
(32+S)-25=25
(32+S)=25+25
32+S=50
S=50-32
S=18
(72+S-40)-(30-10+5)=25
(32+S)-25=25
(32+S)=25+25
32+S=50
S=50-32
S=18