Question

calculati 111+222+333+...+999​

Answer 1

Răspuns:

111+222+333+...+999​=111·(1+2+...+9)=

111·(9·10/2)=

111·(90/2)=

111·45=4995

suma lui Gauss

Answer 2

Răspuns:

notam suma cu S

S=111+222+333+...+999

S=1×111+2×111+3×111+...+9×111

S=111(1+2+3+4+5+6+7+8+9)

S=111×45

S=4995