1.( A+b+c+d):4≈75
a+b+c+d≈75·4
a+b+c+d≈300
2.(a+b+c):3≈665
713+b+c≈665·3
713+b+c≈1995
A+b≈1995-713
A+B≈1282
(a+b):2≈?
1282:2≈641
3. 11+12+.......+100≈5·(1000X-1)
S≈ 11+12+......+100
S≈100+99+...+11
2S≈111+111+...+111
NUMAR TERMENI≈(111-11):1+1
NUMAR TERMENI≈101
S≈(101·111):2≈5 100,5
5100,5≈5:(1000X-1)
1000X-1≈5100,5·5
1000X-1≈25502,5
1000X≈25502,5-1
DE AICI M-AM BLOCAT SPER SA ITI DAI SEAMA SCUZE
