The United States averages about $13,700 and change spending per pupil on education k-12. For the sake of argument, let's just say that of all the DACA kids here, the average is about 6 years of school (half of 12 is 6). Follow along here.
That means that, on average, we are into each DACA kid about $80,000. 80 grand. Toss in the kids in college and it goes up but let's use $80K for right now. $80,000 x 750,000 DACAs= $60 BILLION. Toss in a few billion more in transportation (back to somewhere), incidental costs, ICE salaries, etc. and it adds up.
So we get rid of all of them and we piss $60-65 billion dollars down the drain.
Now that's math that the Donald understands. Its like the casino business; everybody lost.