The current mega-millions jackpot is $640M, which gives you a lump-sum payment of $462M. Applying a federal tax rate of 25%, state tax of 0-10% and giving a little to your wife to spend, you’ll be left with about $300M (rounded).
The number of possible combinations is 176 million. Assume 300 million tickets are sold (just doubling the increase in jackpot since last drawing and rounding off). Should you buy a ticket or not? How about 2 or more?