Some schools provide access to the (Pearson SuccessNet) where the answer key is hidden in the “Teacher Resources” section. You can also search: "Realidades 1 Guided Practice 2B-4 answers" on Quizlet — many teachers post flashcard sets with the exact answers.
In the answers above:
This chapter, "¡A comprar!", focuses on shopping and fashion. Beyond using adjectives as nouns, the workbook pages around page 87 often cover: Guided Practice Activities 2b-4 Answers Page 87