Tính:
B = 1.2 + 2.3 + 3.4 + ... + 99.100
B=1.2+2.3+3.4+...+98.99+99.100
tính tổng : A=1.5 + 5.9 + ....+97.101+101.105
B=1.2^2+2.3^2+3.4^2+....+99.100^2
C=1.2+3.4+5.6+7.8+...+99.100
D=1.2.3+2.3.4+...+98.99.100
B=1.2+2.3+3.4+...+99.100
A=1.2+2.3+3.4+...+99.100
1.2+2.3+3.4+4.5+...+99.100
1.2+2.3+3.4+.....99.100 =?
1.2+2.3+3.4+...+99.100
1.2+2.3+3.4+....+99.100=???