Why does the flag have 13 stripes?

Why this is the answer

Thirteen colonies broke away from Great Britain, and the thirteen stripes are there to honor them. When the Declaration of Independence was adopted in 1776, those colonies became the first thirteen states. The flag did not always look the way it does now, though. For the first 18 years of independence it carried 13 stripes, but after Kentucky and Vermont joined the Union, two stripes were added in 1794, which left the flag with fifteen. In 1818 Congress settled the matter: the number of stripes would stay at 13 for good, in memory of the original states that had once been British colonies. The states are counted by the stars instead, one star for each state. Each part of the design carries a meaning. Red stands for bravery, white for purity, and blue for justice, and the nickname "the Stars and Stripes" comes from the two features you are asked about in this question and in the one on the 50 stars. Both official answers express the same idea. You can say there were 13 original colonies, or that the stripes represent the original colonies, and because the words in parentheses are optional, a short "13 original colonies" is a complete answer. This question also carries an asterisk on the official list, which puts it among the 20 questions that applicants who qualify for the 65/20 special consideration may study instead of the full list. One mix-up to watch for: stripes and stars get swapped. If you answer "because there are 50 states," you have given the answer to the question about stars. A simple way to keep them apart is to think of the stripes as history that will never change and the stars as a count of the states, one for each.