The most common letter used in the English language is E. The next most common is T. The vowels O, A, and I are the next most common; then comes the letter N. Code breakers (cryptologists) use this information to break simple substitution codes. In the sentence that follows, each letter stands for another. For example, the letter D stands for the same letter every time it occurs. Use what you know or can find out about common letters to decode this message.
DMRA EXCEFX GC RCQ JRCL QBMQ QBX NQOGA CS DMQBXDMQTUN UMR BXFE QBXD WXMG CW LWTQX M UCGX
(Source: Mathematics Teaching in the Middle School, Jan-Mar 1995)