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a fost răspuns

18+19+20+21+...+48

32+33+34+35+...70

25+26+27+28+...+128

34+35+36+37+...+90

Ajutatima .

Răspuns :

Fotbalgol
18+19+20+21+...+48=18+19+20+21+...+48=(18+48):2 ori 30= 990
Milumil2000
18+19+20+21+...+48 = (18+48)*31/2=13392

32+33+34+35+...70=(32+70)*39/2=1989

25+26+27+28+...+128=(25+128)*104/2=7956

34+35+36+37+...+90=(34+90)*57/2=3534

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