You can use
Twentieth.
three lines below each other
forty
No not without a MC number and a dot number
One can write straight without lines by practicing good hand-eye coordination and using a steady hand to guide the pen or pencil in a straight path. This may require focus and patience to maintain a consistent writing direction.
10,000
Yesterday
You need to Spell out the number.
A vertical line has the equation [ x = a number ]. A horizontal line has the equation [ y = a number ].
It is done by using Roman numerals: VI = 6
you write it down! any number without decimals or fractions 1,2,3,4,5,6,7,8,9,10 and so on
When addressing a postcard without lines, write the recipient's name and address neatly in the center of the card. Use a ruler or straight edge to keep the lines straight, and make sure to leave enough space for the stamp and any additional information.