How many numbers are in the first $20$ rows of Pascal's Triangle

uh...210. each row has the numbers that the row is for example the 5th row has 5 numbers.

P.S. i do aops too

REALLY?! What's your username?

What is the 39th number in the row of Pascal's triangle that has 41 numbers?

1 + 2 + 3 + ....+ 19 + 20  = n (n + 1) / 2   = (20)(21)/ 2  = 210

Just as AWESOMEEE  has predicted......nice job  !!!!!

my username is awesomeee for aops

Ok!! I am mathtime7 lol. My mom made up the name...

i...dont know about that 46 row thing

i sent u a friend request

Notice Mellie, that the 39th number in row 41  is the same as the 3rd number in that row....= C(41, 2)  = 820 

Also notice  that, using the combinatoric,  [41 - 2]  = 39  tells us which element we're interested in....!!!!

cphill can u anwser my questions?

Muchomath Mellie 

I LIKE IT  !!!!!

Chris and I have both answered some of your questons Awesomeee   ;)

What does aops stand for :/

It stands for ArtOfProblemSolving

Thanks Mellie