Answer :
Alright so let's think there is a blank one that represents 0 and a 1,2,3,4,5, and 6 in all that's 7 different numbers.
For an example you don't have to do this for every number, but here's how the 0,s might work.
0,0 0,1 0,2 0,3 0,4 0,5 0,6
That is 7 different combinations for only one number but that is not the answer.
There are 7 numbers and 7 combinations.
7x7= 49
The answer is 49 dominos in each set. I feel like a teacher now but I hope this helped you
For an example you don't have to do this for every number, but here's how the 0,s might work.
0,0 0,1 0,2 0,3 0,4 0,5 0,6
That is 7 different combinations for only one number but that is not the answer.
There are 7 numbers and 7 combinations.
7x7= 49
The answer is 49 dominos in each set. I feel like a teacher now but I hope this helped you