1. 400+100-1+1=500-1+1=499+1=500
2. 20/100×40=80/10=8
3.456012×[10-5×(28-26)]=456012×[10-5×2]=456012×1=456012
4. nu stiu sa il fac, scuze
5. 850-825=25
6. (32×3):24=96:24=4
7. 34+32+42=66+42=108
8. 31/15+8/15=39/15=13/5
9. 25/2+53/2=78/2=39
10.3/15-2/15=1/15
11. 3 intregi 1/2+5 întregi 3/4=7/2+23/4 (amplificãm 7/2 cu 2) = 14+23/4=37/4
