Solve 21-(6-13): Order of Operations with Nested Subtraction

To solve this problem, we'll follow these steps:

• Step 1: Evaluate the inner expression $6 - 13$
• Step 2: Substitute the result from Step 1 into $21 - \text{result from Step 1}$

Now, let's work through each step:

Step 1: Calculate $6 - 13$. In this calculation, we subtract 13 from 6. The result is $-7$, because when subtracting a larger number from a smaller one, the result is negative.

Step 2: Substitute $-7$ into the outer expression $21 - (-7)$. Since subtracting a negative is equivalent to adding the positive opposite, this simplifies to $21 + 7$.

Now, compute $21 + 7$, which equals 28.

Therefore, the solution to the problem is $28$.