Klingon originally had a ternary number system; that is, one based on three. Counting proceeded as follows: 1, 2, 3; 3+1, 3+2, 3+3; 2*3+1, 2*3+2, 2*3+3; 3*3+1, 3*3+2, 3*3+3; and then it got complicated. In accordance with the more accepted practice, the Klingon Empire sometime back adopted a decimal number system, one based on ten. Though no one knows for sure, it is likely that this change was made more out of concern for understanding the scientific data of other civilizations than out of a spirit of cooperation.

The Klingon numbers are:

Higher numbers are formed by adding special number- forming elements to the basic set of numbers (1--9). Thus, wa'maH ten consists of wa' one plus the number-forming element for ten, maH. Counting continues as follows:

Higher numbers are based on maH ten, vatlh hundred, and SaD or SanID thousand. Both SaD and SanID are equally correct for thousand, and both are used with roughly equal frequency. It is not known why this number alone has two variants.

Numbers are combined as in English:

5,347 vaghSaD wejvatlh loSmaH Soch or vaghSanID wejvatlh loSmaH Soch

604 javvatlh loS

31 wejmaH wa'

Some of the number-forming elements for higher numbers are:

ten thousand netlh

hundred thousand bIp

million 'uy'

billion Saghan

Zero is pagh.

Numbers are used as nouns. As such, they may stand alone as subjects or objects or they may modify another noun.

mulegh cha' Two (of them) see me.
(mulegh they see me, cha' two)

wa' yIHoH Kill one (of them)!
(wa' one, yIHoH kill him/her!)

The preceding sentence is grammatically correct even without the wa' because the prefix yI- indicates a singular object. The wa', therefore, is used for emphasis only.

Numbers used as modifiers precede the noun they modify.

loS puqpu' or loS puq four children

vaghmaH yuQmey or vaghmaH yuQ fifty planets

The plural suffixes (-pu', -mey) are not necessary when a number is used.

When a number is used for numbering, as opposed to counting, it follows the noun. Compare:

DuS wa' torpedo tube number 1

wa' DuS one torpedo tube

Ordinal numbers (first, second, etc.) are formed by adding -DIch to the numbers.

wa'DIch first

cha'DIch second

HutDIch ninth

Ordinal numbers follow the noun.

meb cha'DIch second guest

Adding -logh to a number gives the notion of repetitions.

wa'logh once

cha'logh twice

Hutlogh nine times

These numbers function in the sentence as adverbials (section 5.4).

"many times" or "time and time again"

Use pIj "often". One way to express this if being emphatic is periphrastically: V 'ej V-qa' ('ej V-qa'…) (where V is the repeated action):

qagh vISoppu' 'ej vISopqa'pu' 'ej vISopqa'pu'
I've eaten gagh many times.

Addition

"4 + 3 = 7" would be wej boq loS; chen Soch (literally, "four allies with three; seven forms"). It is also possible to reverse the two numbers being added: loS boq wej; chen Soch.

Note that in these mathematical constructions, the numbers, even those higher than "one," are considered singular from a grammatical point of view. One says wa' boq cha'; chen wej "2 + 1 = 3" (two allies with one, three forms"), not wa' luboq cha'... That is, the prefix lu-, indicating a third person plural subject and third person singular object, is not used. The subject ("two" in the example) is considered singular.

Subtraction

For subtraction, the suffix -Ha' "undo" is attached to boq producing boqHa', literally "dis-ally" or "dissociate from." Thus "4 - 3 = 1" would be loS boqHa' wej; chen wa' (literally, "three dissociates from four, one forms").

When subtracting, the subject and object cannot be reversed without changing the equation. wej boqHa' loS would be "3 - 4" and the answer would be a negative number (a concept Maltz wanted to postpone for another time).

Multiplication

In Klingon, multiplication involves a number allying with itself. Thus, the suffix -'egh "oneself" is used: boq'egh "ally with oneself." It is the necessary to specify how many times this alliance occurs.

For example, "2 x 3 = 6" would be cha'logh boq'egh wej; chen jav ("twice, three allies with itself, six forms"). The multiplier and multiplicand may be reversed: wejlogh boq'egh cha' ("3 x 2," "three times, two allies with itself").

Division

Paralleling multiplication, division in Klingon involves a number dissociating from itself a specific number of times. The verb used is boqHa''egh "dis-ally from oneself, dissociate from oneself," containing both -Ha' "undo" and -'egh "oneself."

For example, "6 / 3 = 2" is wejlogh boqHa''egh jav; chen cha' ("three times, six dissociates from itself, two forms"). Reversing the dividend and the divisor changes the equation. javlogh boqHa''egh wej would be "3 / 6" and the answer would be a fraction (another topic Maltz didn't want to get into).

Exponents

For exponents, there is a noun qovDa' for the name of the operation, however the idea of raising a number to the power of something is generally expressed by using the verb Sep. For example "2^3=8" is wejlogh Sep’egh cha'; chen chorgh (" 3 times, 2 breeds with itself, eight forms").

Fractions

wej loch cha' 2/3 (two thirds)

vagh loch wej 3/5 (three fifths)

loS loch jav 6/4 (six quarters)

In theory, if appropriate in a mathematical discussion, one could say wa' loch wej "three one–ths". (Though perhaps a little grammatically aberrant, this would not be wa' luloch wej.))

Fractions can be used in sentences as if they are numbers. 

wej loch cha' vIleghpu' I have seen two thirds

vagh loch wej wISoptaH  we are eating three fifths

Negatives

Use Dop to create negative numbers. wej Dop "minus three" or "negative three". Compare this to 'u' Dop "mirror universe".

Random

For random numbers, as when throwing dice, use the verb 'al "float" instead of Haw be random.

mI' al' (a) random number

'al mI' the number is random

There is also a slang expression Du'Hom mI' "random number" (literally "garden number").)

Keeping Score/Tallying

The traditional/old Klingon way of keeping score involves cutting oneself (pe''egh), and this is the term still in use.

A "tally" or "(total) score" follows the same tradition. They say mIvwa'mey, literally "scars" (even though, in traditional scorekeeping, the cuts turn to scabs and eventually go away). This term is also used for "census" or "headcount."

"Out of" is awkward.

loSlogh pe''egh; vaghlogh nID 
cut oneself four times; tried five times.

This is the construction even if the person stopped after four and didn’t really attempt the fifth.

Maltz wasn’t sure how "statistics" would be distinguished from "tally" in this context, but maybe mIvwa'mey poj "tally analysis" or mI' poj "number analysis" would work.

More information on numbers, time, and dates