1) a=4978-2376
a=2602
b=205+2981
b=3186
c=986
a+(b-c)=2602+(3186-986)=2602+2200=4802
2)a+b+c=8339
a+b=5285
b=c-203
a+b+c=8339
5285+c=8339
c=8339-5285
c=3054
b=c-203
b=3054-203
b=2851
a+b=5285
a+2851=5285
a=5285-2851
a=2434
Verificare: a+b+c=2434+2851+3054=8339
Numerele sunt: a = 2434; b = 2851; c = 3054
3) 3954 puieti de brad
3954-432=3522 puieti de tei
3954+3522=7476 puieti de stejar
Total: 3954+3522+7476=14952
Elevii au plantat 14952 de puieti