Notam cu X numarul de papusi
3 × X = X : 2 + 25
3 × X - X : 2 = 25
3×X |___|___|___|___|___|___|
X:2 |___|
6 segmente egale - 1 segment egal = 5 segmente egale = 25
25 : 5 = 5 (un segment egal)
3×X = 5×6 = 30
X:2 = 5
X = 5×2 = 10
Verificare:
3×10 = 10:2+25
30 = 5+25
30 = 30
Irina are 10 papusi.