765+567=1332 mandarine trimise
3109-1332=1777 mandarine ramase
4088-567=3521 banane ramase
1777+3521=5298 fructe total ramase
sau un alt mod
3109+4088=7197 fructe in depozit la inceput
567+(567+765)=567+1332=1899 fructe trimise
7197-1899=5298 fructe total ramase