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calculati sumele S=43+44+45...97 suma lui Gauss si a doua S=57+58+59+60+...+143

Răspuns :

S=43+44+45+...+97=(1+2+3+...+97)-(1+2+3+...+42)=97*98/2-42*43/2=97*49-21*43=4753-903=3850
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S=57+58+59+..+143=(1+2+3+...+143)-(1+2+3+...+56)=143*144/2-56*57/2=143*72-28*57=10296-1596=8700.