Question

adunarea fractiilor cu suma Gauss atunci cand lipsesc nr. Ex:3+6+....+48

Answer 1

3+6+.....+48=
1×3+2×3+....+3×16=
3×(1+2+3+.....+16)=
3×[(16×17)÷2]=
3×(272÷2)=
3×136=
=408