Matematică
wkclaudia
2015-11-13 05:30:42
5+10+15+20+25+...+100
Răspunsuri la întrebare
cameliaandrada
2015-11-13 06:04:39

5+10+15+20+25+...+100= 5×(1+2+3+4+5+...+20)= 1+2+3+...+20= (1+20)×20:2= 420:2=210 5×210=1050

sofia2002345
2015-11-13 06:05:54

5+(5×2)+(5×3)+(5×5)+(5×6)+(5×7)+(5×8)+(5×9)+(5×10)+(5×11)+(5×12)+(5×13)+(5×14)+(5×15)+(5×16)+(5×17)+(5×18)+(5×19)+(5×20)= 5×(1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19)= 5×210=1050

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