Answer :
Answer:
6 of them are used books
Step-by-step explanation:
6+7=13. 7 new book and add 6 more book that will be used, it will equal out in addition = 13
Answer:
6 of them are used books
Step-by-step explanation:
6+7=13. 7 new book and add 6 more book that will be used, it will equal out in addition = 13