Răspuns :
Adaugam :1+2+3+4+5+...+10 si obtinem :
1+2+3+4+5+...+18-(1+2+3+...+10)=
=18•19/:2-10•11:2=
=171-55=
=116.
Sper ca te-am ajutat !
1+2+3+4+5+...+18-(1+2+3+...+10)=
=18•19/:2-10•11:2=
=171-55=
=116.
Sper ca te-am ajutat !
1+2+3+4+5+6+7+8+9+10+11+12+...+18-(1+2+3+4+...+10) =
= [18•(18+1)]/2 - [10•(10+1)]/2 =
= (18•19)/2 - (10•11)/2 =
= 9•19 - 5•11 =
= 171 - 55 =
= 116