The postal exam is given to potential candidates wishing to become permanent employees. The test consists of four parts: Part A, Address Comparison; Part B, Forms Completion; Part C, Number Series; and Part D, Personal Characteristics and Experience. Temporary workers can work without first taking the test but must sit for the exam before being hired permanently.
Part C: Number Series
Part C of the postal exam tests your memory. It consists of a sequence of addresses, and you must determine where an address fits in that sequence. Unlike other sections of the test, only Part A and C are marked for wrong answers so guessing isn't recommended.
There are sample tests offered to prepare you for the postal exam, and they are free. They can be obtained online at the USPS website, or you can check out a book from your local library from which to practice. It is wise to use these practice or sample tests as a way to be better prepared but also to memorize the different sections on the test as they don't change. For example, on the memory portion of the test you will be shown a guide with codes from which to refer. There will be a similar guide on the actual test, so it's best to become familiar with it now.
A mnemonic exercise can be used to help your memory by linking a word to something you want to remember. A number mnemonic exercise is helpful to memorize any series of numbers such as an address, phone number and social security number and may help with Part C of the postal exam. The idea is to first memorize a letter or word association that represents each number. You would make up these words or letters and then use it to recall that number when needed. For example, 1 is fun, 2 is shoe, 3 could be knee, 4 could be more, five is jive and so on. Now, suppose you wanted to recall 413 and 534; you could make a sentence for them from the words you've linked to those numbers. Using the example above, 419 could be "More fun knee" and 534 could be "Jive knee no more." The idea is to come up with words that have meaning to you. It is important that they rhyme with the number because it is easier to remember a rhyming word more so than a random word.
Nutrition & Exercise
Proper nutrition and exercise can affect your health as well as your memory according to Helpguide. Exercise enables oxygen to get to the brain, and this promotes clearer thinking and improved memory. It also points out the importance of getting enough vitamins, in particular B6, B12, C, E and folic acid, all of which support the flow of oxygen.