## Chapter 18: lojbau mekso: Mathematical Expressions in Lojban

### 22. Four score and seven: a mekso problem

Abraham Lincoln's Gettysburg Address begins with the words “Four score and seven years ago”. This section exhibits several different ways of saying the number “four score and seven”. (A “score”, for those not familiar with the term, is 20; it is analogous to a “dozen” for 12.) The trivial way:

```✥22.1    bize
eight seven
87
```

✥22.1 is mathematically correct, but sacrifices the spirit of the English words, which are intended to be complex and formal.

```✥22.2    vo pi'i reno su'i ze
four times twenty plus seven
4 × 20 + 7
```

✥22.2 is also mathematically correct, but still misses something. “Score” is not a word for 20 in the same way that “ten” is a word for 10: it contains the implication of 20 objects. The original may be taken as short for “Four score years and seven years ago”. Thinking of a score as a twentysome rather than as 20 leads to:

```✥22.3    mo'e voboi renomei su'i ze
the-number-of four twentysomes plus seven
```

In ✥22.3, “voboi renomei” is a sumti signifying four things each of which are groups of twenty; the “mo'e” and “te'u” then make this sumti into a number in order to allow it to be the operand of “su'i”.

Another approach is to think of “score” as setting a representation base. There are remnants of base-20 arithmetic in some languages, notably French, in which 87 is “quatre-vingt-sept”, literally “four-twenties-seven”. (This fact makes the Gettysburg Address hard to translate into French!) If “score” is the representation base, then we have:

```✥22.4    vo pi'e ze ju'u reno
four ; seven base 20
4720
```

Overall, ✥22.3 probably captures the flavor of the English best. ✥22.1 and ✥22.2 are too simple, and ✥22.4 is too tricky. Nevertheless, all four examples are good Lojban. Pedagogically, these examples illustrate the richness of lojbau mekso: anything that can be said at all, can probably be said in more than one way.