Number 1 -

: Every whole number is simply a collection of 1s added together. In Symbol and Word

: Anything multiplied by 1 stays exactly the same ( ), making it the multiplicative identity .

: Spelled O-N-E , it originates from the Old English word ān .

: In math, it is called a "unit" and is the only number that is neither prime nor composite.

If you're looking for a simple way to remember how to write it:

: In early learning, it’s often shown as a single dot on a die, one finger held up, or one tally mark. A Rhyme for Formation

: Most commonly a single vertical line, sometimes with a serif at the top or a small bar at the base.