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
You need to Spell out the number.
Yesterday
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
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.
you write it down! any number without decimals or fractions 1,2,3,4,5,6,7,8,9,10 and so on