How many peices are in a standard dominoes set?

i counted mine but forgot how many there are supposed to be, and the box doesn't say.How many peices are in a standard dominoes set?
I KNOW there are 28:



Doubles:

Blank through 6 doubles = 7;



Combination Dominoes:

7 dominoes (blank to 6), 6 combinations with every other number = 42 (7*6 permutation), but since you do not have duplicates like 5:3 and 3:5, divide by two: 42/2 = 21



7 Doubles plus 21 combinations = 28 total dominoes.How many peices are in a standard dominoes set?
mine has 3How many peices are in a standard dominoes set?
28How many peices are in a standard dominoes set?
I think 28