• with Bud's ability to prepare himself to receive bad news. Bud does not want to be caught off guard by seemingly harmless phrases and keeps his guard up to avoid being emotionally scarred. Rule #16 is "If a Grown-up Ever Starts a Sentence by Saying "Haven't You Heard," Get Ready, 'Cause What's About to Come Out of Their Mouth Is Gonna Drop You Head first into a BoilingTragedy."

• Rule #39 allows Bud to emotionally prepare himself to deal with an adult who is crying. Rule #39 is "The Older You Get, the Worse Something Has to Be to Make You Cry."

Bud lives by a set of rules he has composed titled "Rules and Things for a Funner Life and Making a Better Liar Out of Yourself." Some of these rules were adapted from bits of wisdom his mother passed down to him and some are his own thoughts.

These rules could be categorized into those that help Bud survive and those that help Bud thrive.

Five rules that help Bud survive are:

#3 If you got to tell a lie, make sure it’s simple and easy to remember.

#16 If a grown-up ever starts a sentence by saying “Haven’t you heard,” get ready, ’cause what’s about to come out of their mouth is gonna drop you head first into boiling tragedy.

#29 When you wake up and don’t know for sure where you are at and there’s a bunch of people standing around you, it’s best to pretend you’re still asleep until you can figure out what’s going on and what you should do.

#8 Whenever an adult tells you to listen carefully and talks to you in a real calm voice do not listen, run as fast as you can because something terrible is just around the corner.

#63 Never, ever say something bad about someone you don’t know—especially when you’re around a bunch of strangers. You never can tell who might be kin to that person or who might be a lip-flapping, big-mouth spy.

Five rules that help Bud thrive are:

#39 The older you get, the worse something has to be to make you cry.

#87 When an adult tells you they need your help with a problem get ready to be tricked—most times this means they just want you to go fetch something for them.

#328 When you make up your mind to do something, hurry up and do it, if you wait you might talk yourself out of what you wanted in the first place.

#83 If a adult tells you not to worry, and you weren’t worried before, you better hurry up and start ’cause you’re already running late.

#118 You have to give adults something that they think they can use to hurt you by taking it away. That way they might not take something away that you really do want.

Throughout Bud's journey to Grand Rapids to find Herman Calloway, who ends up being his grandfather, Bud lives by a set of rules he created to help him survive as a homeless orphan during the Depression. Bud mentions several rules that help him maneuver safely through life and serve as warnings to avoid precarious situations. Bud's rules also protect his emotions and help him psychologically prepare himself for certain situations.

In chapter 13, Bud is eating with Herman Calloway's band members, who caution Bud not to call Herman "Daddy" or "Poppa." Bud accidentally responds by referring to Herman as a "mean old coot," and immediately slaps his hand over his mouth. Bud then recalls Rule Number 63, which is "Never, Ever Say Something Bad About Someone You Don't Know—Especially When You're Around a Bunch of Strangers. You Never Can Tell Who Might Be Kin to That Person or Who Might Be a Lip-Flapping, Big-Mouth Spy" (Curtis, 98). This rule allows Bud to avoid precarious situations with other people by warning him to avoid saying negative things about certain people in front of strangers. Bud knows from experience that there is a possibility that he can offend someone, which will only cause more drama in his life.

After Herman learns about his daughter's death, he becomes emotional, and Bud sees him crying. Bud then recalls Rule Number 39, which is "The Older You Get, the Worse Something Has to Be to Make You Cry" (Curtis, 135). This rule allows Bud to recognize and understand adults better. Bud knows that Herman Calloway must be seriously suffering because he is crying, which is rare for adults. This rule also allows Bud to sympathize with Herman, and Bud realizes that he is stuck "square in the middle of one of those boiling tragedies."

"When one door closes, another door opens."

"Rule 39 - The older you get, the worse something has to be to make you cry."

"Rule 29 - When you wake up and don't know for sure where you are at and there's a bunch of people standing around you, it's best to pretend you're still asleep until you can figure out what's going on."

In Christopher Paul Curtis's Bud, Not Buddy, Bud's rules help him to survive by reminding him to be wary of adults and to be prepared for disappointment and difficulties.

Bud describes his rules as "the things I think of all the time and try to remember so I don't make the same mistake more than seven or eight times." He has memorized these useful maxims carefully and given them the title:

Bud Caldwell's Rules and Things for Having a Funner Life and Making a Better Liar Out of Yourself.

This title is misleading. First, despite Bud's flippant tone, most of the rules he tells the reader are concerned with survival, not with having fun. Second, they are principally ways of dealing with the dishonesty of adults rather than becoming a better liar oneself.

Rule 83, for instance, states that if an adult tells you not to worry, you should start worrying. Bud continually has to deal with disappointment and dishonesty, as well as outright hostility, in the poverty-stricken landscape through which he travels. These disappointments begin on the first page of the novel, when he is separated from his friend Jerry and dispatched to a new and hostile environment with the Amos family.

The trite maxims that Bud's mother taught him—that whenever one door closes another opens, for instance—prove untrue, and he has to come up with his own tougher philosophy to face such antagonists as Todd and, for a time, Herman. Rule 8 (out of at least 328) is curiously specific and shows that Bud has faced violence more often than most boys of his age:

Whenever an Adult Tells You to Listen Carefully and Talks to You in a Real Calm Voice Do Not Listen, Run as Fast as You Can Because Something Real Terrible Is Just Around the Corner. Especially If the Cops Are Chasing You.

Bud's precarious situation and his lack of a family make such rules necessary for survival as he makes his difficult journey across Michigan.

I wish that I could give you a definitive answer, but that is just not possible.  Bud Caldwell doesn't rank his "Rules and Things to Have a Funner Life and Make a Better Liar Out of Yourself."  He numbers his rules for sure, but they are not ordered in any sort of hierarchy.  In fact, as the book progresses, it becomes clear that Bud just makes up a number to go along with whatever rule that he is about to give the reader.  That suspicion should start creeping into a reader's mind when Bud brings up rule number 328.  Really?  328?  That's a lot of rules that Bud supposedly has memorized.  But late in the story, Bud reminds readers about rule number 547.  The reader has never encountered that number before, but Bud says that he already told the reader about the "worry" rule.  

The first thing to worry about was Rules and Things number 547, or something, that was the one about when a adult tells you, "Don't worry."

You can see from the quote that Bud can't remember exactly which rule number the rule really is.  The "worry rule" that Bud is talking about was actually rule number 83.  

If an Adult Tells You Not to Worry, and You Weren't Worried Before, You Better Hurry Up and Start 'Cause You're Already Running Late.

As you can see, I would like to tell you that Bud has a specific number and rule in mind, but the numbers keep changing.  Bud also never says that a particular rule is more important than any other rule.  To Bud, each rule is very situational.  So the most important rule to Bud will be the rule that best applies to the situation that he is in currently.