mathematics

Undecimber

Undecimber is a mathematics topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Undecimber rather than just read about it. In short: Undecimber or Undecember is a name for a thirteenth month in a calendar that normally has twelve months. Etymology The word undecimber is based on the Latin word undecim meaning "eleven".

Key takeaways

Undecimber belongs to mathematics; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Undecimber to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Undecimber from memory before moving on to harder problems.

Reference excerpt

Undecimber or Undecember is a name for a thirteenth month in a calendar that normally has twelve months.

Etymology The word undecimber is based on the Latin word undecim meaning "eleven". It is formed in analogy with December, which, though the twelfth month in the Gregorian calendar, derives from decem meaning "ten". The Oxford Latin Dictionary defines it as "a humorous name given to the month following December".

Roman use Some modern authors, including the World Calendar Association and Isaac Asimov have reported the names "Undecember" and "Duodecember" for the two intercalary months inserted between November and December upon the adoption of the Julian calendar in 44 BC. This claim has no contemporary evidence; Cicero refers to the months as "intercalates prior and intercalates posterior" in his letters. Historian Cassius Dio tells that Licinus, procurator of Gaul, added two months to the year 15 BC, because taxes were paid by the month. Dio, who wrote in Greek, says Licinus "called [the added months] the eleventh and the twelfth"; August Immanuel Bekker suggested the Latin names might have been "Undecember" and "Duodecember". The abbreviation Unde appears in a Roman inscription from Vercellae in Cisalpine Gaul, dating between the first century BC and the first century AD.

Computing In the Java Platform, Standard Edition, the java.util.Calendar class includes support for calendars which permit thirteen months. Although the Gregorian calendar used in most parts of the world includes only twelve months, there exist some lunar calendars that are divided into synodic months, with an intercalary or "leap" month added in some years. For example, in the Hebrew calendar seven years out of every nineteen (37%) have the "embolismic month" Adar I. The constant java.util.Calendar.UNDECIMBER represents such a month.

Accounting In accounting, a thirteenth month is sometimes used to adjust financial statements for an entire year without affecting monthly results. For example, an organization may wish to adjust its books to reflect the fact that some of its sales and resulting payments due from customers will not be paid. If an organization only does this once per year the organization can attribute these adjustments to "Month 13" so as not to inaccurately post a full year's worth of write offs to one month.

Worked examples

Example 1 — a first encounter with Undecimber

Start with the simplest possible case. Write down what Undecimber claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In mathematics, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Undecimber before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Undecimber ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Undecimber

In research: Undecimber appears in mathematics research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Undecimber in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Undecimber is common in secondary-school and first-year university syllabi. It links to neighbouring topics 13 (number), Latin words and phrases, Months, so understanding it makes those chapters shorter.
In everyday life: Look for Undecimber outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Undecimber in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Undecimber means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Undecimber out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Undecimber in simple terms?

Undecimber or Undecember is a name for a thirteenth month in a calendar that normally has twelve months. Etymology The word undecimber is based on the Latin word undecim meaning "eleven".

Why does Undecimber matter?

Because it connects several mathematics ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Undecimber?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Undecimber.