Solution:
Given:
Tonya has 50 stamps.
Ann has 5 less stamps than Tonya.
Pam has 12 fewer stamps than Ann.

To find the total number of stamps, we'll first determine the number of stamps Ann and Pam have.

Ann's stamps:
Since Ann has 5 fewer stamps than Tonya, Ann has 50 - 5 = 45 stamps.

Pam's stamps:
Pam has 12 fewer stamps than Ann, so Pam has 45 - 12 = 33 stamps.

Now, to find the total number of stamps, we'll add up the individual counts:

Total number of stamps = Tonya's stamps + Ann's stamps + Pam's stamps
= 50 + 45 + 33
= 128

Therefore, the three girls have a total of 128 stamps altogether.