Solve the Subtraction Equation: 699-699 and Find the Difference

The problem asks us to calculate $699 - 699$. In mathematics, there is a straightforward rule: any number subtracted from itself equals zero. This is because you are essentially taking a value away from itself, leaving nothing behind.

• Step 1: Identify the numbers involved in the subtraction: Both numbers are 699.
• Step 2: Apply the arithmetic property: Subtract the number from itself: $a - a = 0$.
• Step 3: Perform the calculation: $699 - 699 = 0$.

Thus, according to the property of subtraction, the result of subtracting a number from itself is always zero.

Therefore, the solution to the problem is $0$.