1. The problem is to understand the number 1. 2. Number 1 is the integer that comes before 2 and after 0. 3. It is the multiplicative identity, meaning for any number $a$, $a \times 1 = a$. 4. It is also the first positive integer and the basis of counting. 5. Therefore, the number 1 is fundamental in mathematics as the building block of all other numbers. Final answer: 1