My textbook
Managerial Economics: A Problem Solving Approach is a succinct textbook built around teaching just enough economics to allow a student to think through and solve practical business problems.
The textbook is supported by a popular blog with entries referenced by relevant chapter number, as well as Cengage's MindTap software, a set of videos for each lecture, a large test bank, and a detailed instructor's guide.
For a bit of (textbook-promotional) fun, let the MBA Oracle do all of your business BS writing for you.
There is also a set of minimalist lecture slides I used when teaching from this book.
The sixth edition is expected in 2022.