When using the acquisition method, how do we know whether to use BOOK VALUE or FAIR VALUE?

CFA Level II FRA
#1

When adding the acquired’s Assets & Liabilities to the Parent’s Balance Sheet - how do we know whether to use book values or fair values (in the instance where we have BVs and FVs for both).

Thank you.

Context:

A particular question adds the FAIR VALUE of the acquired’s long term debt to the BOOK VALUE of the parent’s long-term debt.
How was this decided?

My understanding is IFRS/US GAAP require the acquirer measure the assets and liabilities of the acquired entity at FAIR VALUE as of the date of the acquisition.

#2

Your understanding is correct: IFRS/US GAAP does require the acquirer to book the assets and liabilities of the acquired entity at fair value as of the date of the acquisition.