Question

-1-2+3+4-5-6+7+8-9-10+.......-2018+2019+2020= ?​

Answer 1

Răspuns:

Explicație pas cu pas:

grupam termenii patru cate 4 si avem:

-1-2+3+4-5-6+7+8-9-10+11+12+.....-2017-2018+2019+2020= (-1-2+3+4)+(-5-6+7+8)+(-9-10+11+12)+.....+(-2017-2018+2019+2020) = 4+4+4+...+4 ( de 2020:4 =505 ori deoarece am grupat termenii 4 cate 4) = 4·505=2020