Question

Calculati prin suma lui Gauss
: 2+4+6+...........+100= ;

3+6+9+12+..........+2019= ;

4+8+12+..........+2020= ;

7+14+21+...........+2023= .

Answer 1

2+4+6+...........+100= (2+100)·50:2 = 102·25 = 2550

100:2 = 50 termeni

3+6+9+12+..........+2019= (3+2019)·673:2 = 1011·673 = 680403

2019:3 = 673 termeni

4+8+12+..........+2020= (4+2020)·505:2 = 1012·505 = 511060

2020:4 = 505 termeni

7+14+21+...........+2023= (7+2023)·289:2 = 1015·289 = 293335

2023:7 = 289 termeni