Question

daca scad dintr-un numar 30 si apoi adug 20,obtin 50.Care este nr?

Answer 1

x-30+20=50
x=50-20+30
x=60

Answer 2

30+20=50
50-30=20                  fals
20+20=40

30+30=60
60-30=30                  adevarat
30+20=50
Am rezolvat prin incercari .