Final answer:
All thirteen states had to approve the Articles of Confederation and any changes to it.
Step-by-step explanation:
The Articles of Confederation required the approval of all thirteen states for any changes to be made. This made amending the Articles extremely difficult and rare. The framers of the Constitution learned from this and created a new method for amending the Constitution, which required a two-thirds majority in both houses of Congress and the approval of three-quarters of state legislatures.