The following cmavo are discussed in this section:

ci'i |
PA |
infinity |

ka'o |
PA |
imaginary i, sqrt(-1) |

pai |
PA |
π, pi (approx 3.14159...) |

te'o |
PA |
exponential e (approx 2.71828...) |

fi'u |
PA |
golden ratio, Φ, phi, (1 + sqrt(5))/2 (approx. 1.61803...) |

The last cmavo is the same as the fraction sign cmavo: a fraction sign with neither numerator nor denominator represents the golden ratio.

Numbers can have any of these digit, punctuation, and special-number cmavo of Sections 2, 3, and 4 in any combination:

Note that
* ka'o* is both a special number (meaning
“i”) and a number punctuation mark (separating the real and the imaginary parts of a complex number).

The special numbers
* pai* and

However, many combinations are as yet undefined:

Example 18.21 is not “1 minus 2”, which is represented by a different cmavo sequence altogether. It is a single number which has not been assigned a meaning. There are many such numbers which have no well-defined meaning; they may be used for experimental purposes or for future expansion of the Lojban number system.

It is possible, of course, that some of these “oddities” do have a meaningful use in some restricted area of mathematics. A mathematician appropriating these structures for specialized use needs to consider whether some other branch of mathematics would use the structure differently.

More information on numbers may be found in Section 18.8 to Section 18.12.