What task did the government do well under the articles of confederation?

When the Articles of Confederation were written, they intentionally gave more power to the states, and not to the central government. Unfortunately, the weakness of the central government created problems:  

1) Under the Articles there was only a unicameral legislature so that there was no separation of powers.  

2) The central government under the Articles was too weak since the majority of the power rested with the states.  

3) Congress, under the Articles, did not have the power to tax which meant that they could never put their finances in order.(eg. pay war debts, foster a diverse, healthy American economy.)  

4) In order to change or amend the Articles, unanimous approval of the states was required which essentially meant that changes to the Articles were impossible.  

5) For any major laws to pass they had to be approved by 9 or the 13 states which proved difficult to do so that even the normal business of running a government was difficult.  

6) Under the Articles, Congress did not have the power to regulate commerce which caused competition between states as well as diplomatic issues. (Each state had their own currency, of different values. Not every state accepted the other's currency. Each had different tax rates.)

pepin the short[a] (german: pippin der kurze, french: pépin le bref, c. 714 – 24 september 768) was the king of the franks from 751 until his death. he was the first of the carolingians to become king.[b][2]

the younger son of the frankish prince charles martel and his wife rotrude, pepin's upbringing was distinguished by the ecclesiastical education he had received from the monks of st. denis. succeeding his father as the mayor of the palace in 741, pepin reigned over francia jointly with his elder brother carloman. pepin ruled in neustria, burgundy, and provence, while his brother carloman established himself in austrasia, alemannia and thuringia. the brothers were active in suppressing revolts led by the bavarians, aquitanians, saxons, and the alemanni in the early years of their reign. in 743, they ended the frankish interregnum by choosing childeric iii, who was to be the last merovingian monarch, as figurehead king of the franks.