I think you might be better off illustrating big number points using the big numbers. It's very easy for someone not familiar with scientific notation to miss the huge difference between 7.889608E+23 tons and 1.9891E+27. But if you write the numbers out, one on top of the other:
1,989,900,000,000,000,000,000,000,000
- 788,960,000,000,000,000,000,000
1,989,100,000,000,000,000,000,000,000
it's much easier to see that the lost mass is irrelevant to the total amount of mass.
I tend to also doubt his claimed age of 20, but if that is accurate, it's still evident from his writing that he's not real bright. In that circumstance, KISS.
Ridicule is the only weapon which can be used against unintelligible propositions. -- Thomas Jefferson
We see monsters where science shows us windmills. -- Phat
It has always struck me as odd that fundies devote so much time and effort into trying to find a naturalistic explanation for their mythical flood, while looking for magical explanations for things that actually happened. -- Dr. Adequate
...creationists have a great way to detect fraud and it doesn't take 8 or 40 years or even a scientific degree to spot the fraud--'if it disagrees with the bible then it is wrong'.... -- archaeologist