Respuesta :

offguard

When you add consetituve numbers, the formula is [tex]1+2+3+4+...+n=\frac{n(n+1)}{2}[/tex].

Therefore, plugging in 20, you get 20*21/2=210.


lily9211

Answer:

210

Step-by-step explanation:

You can just add these terms up.

1 + 2 + 3 + 4... + 20 is the same as writing out:

1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 11 + 12 + 13 + 14 + 15 + 16 + 17 + 18 + 19 + 20

Add the numbers together to get your answer of 210.

good job