This textbook is the one I kept after the course ended for reference.
*Mathematics for Plumbers and Pipefitters 8th Edition Paperback – 9781111642600
What stands out about this textbook is the way each concept is introduced with a question.
Mathematics for Plumbers and Pipefitters by Lee Smith, 8ed (English, Paperback)
A nice touch in this textbook is the list of suggested readings at the end.