How many dots on full set of dominoes?

Answer 1

Each number appears once with every other number and once with blank and once with itself.

So for 1 there are

1. 0 - 1
2. 1 - 1
3. 2 - 1
4. 3 - 1
5. 4 - 1
6. 5 - 1
7. 6 - 1

and, as the double-1 must be included twice, there are eight 1s in a set.

Similarly, there are eight of all the other numbers too.

So, as 1+2+3+4+5+6 = 21 and 21x8 = 168, there are 168 dots on a blank-to-six set of dominoes.

Answer 2

Sets come in various sizes, ranging from a double-six set (28 tiles) to a double-eighteen (190 tiles).