Răspuns :
40:2×3:2 = 20×3:2 = 60:2 = 30 (diferenta)
2×30+10×3×3:2 = 60+30×3:2 = 60+90:2=60+45 = 105 (descazutul)
105-s = 30
s = 105-30
s = 75( scazatorul)................
2×30+10×3×3:2 = 60+30×3:2 = 60+90:2=60+45 = 105 (descazutul)
105-s = 30
s = 105-30
s = 75( scazatorul)................