Question

cum se rezolva exercitiul (1+2+3+...+56)-(1+2+3+...36)?

Answer 1

1+2+3+.....+56=
56+55+54+....+1
S2=57X56
S2=3192
S=3192:2
S=1596
1+2+3+...+36
36+35+34+.....+1
S2=37X36
S2=1332
S=1332:2
S=666
1596-666=930

Answer 2

1+2+3+....+56=(56+1)*56:2=1596{suma lau gauss}
1+2+3+...+36=(36+1)*36:2=666
1596-666=930