Răspuns :
I----I----I+12
I----I
egalam partile:312-12=300
aflam al 2 lea nr:300÷3=100
aflam primul nr:100×2+12=212
I----I
egalam partile:312-12=300
aflam al 2 lea nr:300÷3=100
aflam primul nr:100×2+12=212