What is the highest number you can pick in each of those lottos?
My memory of combinatorics is really fuzzy, but if I assume the numbers can be from 1-40 and can't repeat, then:
Picking 4 specific balls in one lotto is 40*39*38*37 = 2,193,360
Or, in math class, you'd write it as 40!/36! (order of the balls does not matter)
I think you would square this to determine the chances of drawing the same 4 balls a second time. (?)
4,810,828,089,600 (4.8 trillion)
And this would apply to any string of 4 numbers matching, not just 12-19-30-34. For a range of 1-50, this becomes 30,549,939,840,000. (30 trillion)
*Disclaimer: My math might suck, but it amused me to try.