Question

Calculati: 1997+2 x (1 + 2 + 3 + ... + 1996

Answer 1

1997 + 2 × (1 + 2 + 3 + ... + 1996) =

1997 + 2 × (1996 + 1) × 1996 : 2 =

1997 + 1997 × 1996 =

1997 × (1 + 1996) =

1997 × 1997 =

1997^2
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Answer 2

1 997 + 2 x ( 1 + 2 + 3 + ........ + 1 996 ) =

= 1 997 + 2 x 1 996 x ( 1 + 1 996 ) / 2 =

= 1 997 + 1 996 + 1 997 =

= 1 997 x ( 1 + 1 996 ) =

= 1 997 x 1 997 =

= 1 997² =

= 3 988 009