Given the task definition and input, reply with output. In this task, you are given a sentence and question which can be answered using the sentence. Your task is to answer the question using the information from the sentence. The answer to the question is unique and it is a continuous text span from the sentence.

Sentence: Instead , much of numerical analysis is concerned with obtaining approximate solutions while maintaining reasonable bounds on errors . 
 Question: what might something maintain?

reasonable bounds on errors