Question

calculati grupand convenabil termeni.
2+4+6+......+18+20

Answer 1

(2+18)+(4+16)+(6+14)+(8+12)+(10+20)

Answer 2

grupam termenii in asa mod incat suma lor sa dea 20
2+18=20
4+16=20
6+14=20
8+12=20
10
20
vei avea 20+20+20+20+10+20=110