1. The problem is to find the sum of the numbers 2, 7, 2, and 1. 2. The formula for the sum of numbers is simply adding them together: $$\text{Sum} = a + b + c + d$$ where $a=2$, $b=7$, $c=2$, and $d=1$. 3. Substitute the values into the formula: $$\text{Sum} = 2 + 7 + 2 + 1$$ 4. Perform the addition step-by-step: $$2 + 7 = 9$$ $$9 + 2 = 11$$ $$11 + 1 = 12$$ 5. Therefore, the sum of the numbers 2, 7, 2, and 1 is $$12$$.