For the Early Bird Singapore books, there's not separate text and work books. It's just Early Bird 1A, 1B, 2A and 2B. That can be confusing, because the next level after Early Bird 2B is 1A.
I bought both the text and the workbook for 1A and 1B, but after that, I've only bought the textbooks. I found there wer plenty of practice problems in the textbook for my kids. I still let my kids do anything orally that they are capable of doing in their heads.
Somewhere in the Early Bird books, it goes into the words for numbers. For those pages, I just printed out stickers with the number names for them to peel and stick in the proper places. I figured the point of the exercise was for them to recognize the words, not for them to practice writing the letters, which would have been frustrating for them.