1. The problem is to multiply 1 by 1. 2. The multiplication formula is $a \times b = c$, where $a$ and $b$ are numbers and $c$ is their product. 3. Here, $a = 1$ and $b = 1$. 4. Multiplying these, we get $1 \times 1 = 1$. 5. Therefore, the final answer is $1$.