Numbers (props or theings stand alone) are usually written as digits.

Hand v 5 fingers

Tens

Multiples of ten are, in writing, composed by -ty after the root:

Nine                     ninety (9ty)
Eight                    eighty (8ty)
Seven                   seventy
Six                         sixty
Five                       fivety
Four                     fourty
Three                   threety
Two                      twoty

10 – 20

The only exception is teen (ten) that exists besides ‘onety’.

Nineteen – onetynine
Eightteen – onetyeight
Seventeen  – onetyseven
Sixteen  – onetysix
Fiveteen – onetyfive
Fourteen – onetyfour
Threeteen – onethree
Twoteen – onetywo
Oneteen – onetyone

Ordinals

De suffix –th converts a number into an ordinal (prop):

Nineteenth, 19th
Seventyth, 70th
Teenth, 10th
Nineth, 9th
Eightth, 8th
Fiveth, 5th
Threeth, 3th
Twoth, 2th
Oneth, 1th

Fraction (a theing or a spec)

De suffix –tr converts a number into a fraction:

Sixtr  (1/6)
Fourtr (1/4)
Threetr (1/3)
Twotr (1/2). Half is permitted as well.