Răspuns:
A-B=40:4=10
A-B=40:4=10A = B + 1O
A-B=40:4=10A = B + 1OA / B = 3
A-B=40:4=10A = B + 1OA / B = 3A = 3E
A-B=40:4=10A = B + 1OA / B = 3A = 3E3B = B + 1O I-B
A-B=40:4=10A = B + 1OA / B = 3A = 3E3B = B + 1O I-B2B = 1O 1:2
A-B=40:4=10A = B + 1OA / B = 3A = 3E3B = B + 1O I-B2B = 1O 1:2B = 5
A-B=40:4=10A = B + 1OA / B = 3A = 3E3B = B + 1O I-B2B = 1O 1:2B = 5A=5+10=15
Succes in continuare!