Everything you need to know to form large numbers, express time, and even do some basic math. There's quite a lot you can do with just the basic building blocks that Kokanu provides.
It's simple enough to talk about the base number words up to 100 that Kokanu provides:
wan  1 (one)
toso  2 (two)
san  3 (three)
nanku  4 (four)
lima  5 (five)
lijo  6 (six)
setan  7 (seven)
etu  8 (eight)
saka  9 (nine)
tiju  10 (ten)
sijen  100 (hundred)
But how do you put these words together to form other numbers? IFor numbers up to 999, it's actually very much like you would do it in English! There is no such thing as a modifier form of a number, they all act as connected nouns. Let's look at examples and it will all be clear.
san tiju toso  32 (three tens and two)
lima sijen lijo  506 (five hundreds and six)
Forming Numbers 1000 and larger
Powers of a thousand (thousand, million, billion, trillion, etc.) are expressed with con followed by the exponent. For example,
It’s important to think of con to mean “thousand to the power of” or “1000x” rather than just “thousand”. The word tan is used after each power of a thousand when adding extra numbers.
nanku tiju san con wan  43,000 ([four tens and three] thousand to the power of ^one)
nanku tiju san con wan tan wan  43,001 ([four tens and three] thousand to the power of ^one, then [one])
san con toso, tan nanku sijen nanku tiju lijo con wan, tan setan tiju etu  3,446,078 ([three] thousand to the power of ^two, then [four hundreds and ten fours and six] thousand to the power of ^one, then [seven tens and eight])
Unlike other words which would be considered modifiers after the first one, no matter how many number words you put together it always counts as a single noun.
Zero
The word nula is used for "zero", though, like in English, it doesn't often appear in compound whole number words. You don't find yourself saying "four thousand, zero hundred, and fifty six", do you? That said, zero is still a very important concept.
Cardinals and Ordinal Numbers
Cardinal numbers are placed before the noun. These are used for counting how many or how much of something there is.
mi le junja in san pawo.  "I have three dogs"
mi le tun tiju etu osa minuli.  "I have been working for eighteen hours
Ordinal numbers are placed after the noun. These are used to specify the position of an item in a series, like "fourth" or "seventeenth".
pawo toso le tope ani.  "The second dog is the best"
san ten putuci je osa tiju etu le conca.  It is 18:03, literally "three minutes after the eighteenth hour have passed"
This is why when telling time, we say san osa to mean "three hours", and "osa san" to mean "three o'clock", literally "third hour".
Fractions, Decimals, and Percents
It's pretty straightforward to talk about whole numbers, but it gets a bit more complicated when you need to discuss numbers with fractional components.
To talk about fractions we use [numerator] osa je [denominator], literally "[numerator] parts of [denominator].
toso tiju nanku osa je toso sijen san tiju wan  24/231
To talk about decimals we use [whole number] pintu [decimal digits]. Decimal digits are stated one by one using single digit number words.
tiju toso pintu san toso nanku nanku  12.3244
san pintu wan nanku wan lima saka toso...  3.141592...
To talk about percentages we add the phrase osa je sijen to the end of the number. This can be combined with decimal notation to specify decimal percentages.
toso tiju lima osa je sijen  25%
nanku tiju pintu etu setan wan osa je sijen  40.871%
Negative Numbers
Negative numbers are stated using opotu je [number] meaning "reflection of [number]" or "opposite of [number]", or [number] je for short.
opotu je nanku osa je tiju  4/10
opotu je lijo pintu saka saka  6.99
Mathematical Operations
While there are no specific words for mathematical operations such as "addition" or "multiplication", other descriptions can be used to talk about the operations in a mathematical context.
Operation 
Kokanu 
Addition 2 + 3 
te tene in san ke toso  literally "to give 3 to 2" te pon ta toso le unitu kan san  literally "to combine 2 with 3" 
2 + 3 = 5 

Subtraction 7  4 
te pon ta nanku le lipan sun setan  literally "to makeabsent 4 from 7" te alu in nanku sun setan  literally "to take 4 from 7" te pon ta setan le papon in nanku  literally "to cause 7 to emit 4" 
7  4 = 3 

Multiplication 2 * 5 
te tun in toso non je lima  literally "to create 2 groups of 5" te pon ta toso le niju kan lima  literally "to makemany 2 with 5" 
2 * 5 = 10 
toso non je lima le tiju  literally "2 groups of 5 is 10" lima niju je toso le tiju  literally "5 (large amounts) of 2 is 10" 
Division 9 / 4 
te pon ta saka le panli wija nanku  literally "to cut 9 using 4" 
9 / 4 = 2.25 
nanku panli je saka le toso pintu toso lima  literally "4 splits of 9 is 2.25" saka osa je nanku le toso pintu toso lima  stating 9/4 in standard fraction form directly 
Exponentiation 6³ 
te pon ta lijo le niju kan sa an san ten  literally "to makemany 6 with itself 3 times" 
6³ = 216 
san niju saman je lijo le toso sijen tiju lijo  literally "3 identical bunches of 6 is 216" 