Please, please, please, help with the calculations of this problem.

When S1 died in 2013 the couple had an ABC estate plan with property as shown below. At S1s death his executor elected to QTIP all of Trust C.

At S1s death:

S1's Separate Property: $7,000,000

Their Community Property: $1,200,000

S2's Separate Property: $4,000,000

QUESTION: Calculate the tax owed by S2s estate had all of S1s property been left outright to S2 and show the difference in estate tax due, first assuming AEA portability was elected by S1's executor and then assuming AEA portability was overlooked.