I am doing an investigation about a game called triminoes (like dominoes). The game is played using triangular pieces of card. Each card has 3 numbers on it. I have to investigate the relationship between the number of trimino cards in a set and the largest number on the cards. I found; largest no. used 0 1 2 3 4

no. of trimino cards 1 4 10 20 35

I was ginen the formula for this which is:

UN= UN - 1 + 1/2 (n + 1 ) (n+2)

UN=no. of trimino cards n= largest no.

I don't know how to get to this equation I think it has something to do with triangle numbers!

Answered by Penny Nom.