Question

Compute 1 + 2 + 3 +....+ 1,997 + 1,998 + 1,999

Answer 1

Answer:

1 999 000

Step-by-step explanation:

Formula:

$1+2+3+.\ .\ .+n=\frac{n\times \left( n+1\right) }{2}$

………………………………………

Then

$1+2+3+....+1997+1998+1999=\frac{1999\times \left( 1999+1\right) }{2}$

$1+2+3+....+1997+1998+1999=\frac{1999\times \left( 2000\right) }{2}$

$1+2+3+....+1997+1998+1999=\frac{3998000 }{2}$

$1+2+3+....+1997+1998+1999=1999000$