8 × 9 + 10 = 72 + 10 = 82
a+b+c+d = 82
a |____|+10
b |____|+20
c |____|+15
d |____|+5
avem 4 segmente egale + 10+20+15+5 = 82
82 - (10+20+15+5) = 82 - 50 = 32
32 : 4 = 8 (un segment egal)
a = 8 + 10 = 18
b = 8 + 20 = 28
c = 8 + 15 = 23
d = 8 + 5 = 13
Verificare:
18 + 28 + 23 + 13 = 82