Evaluate: `78xx82`

Answer

To evaluate \( 78 \times 82 \) using the difference of squares method, we can follow these steps:

### Step-by-Step Solution:

1. **Rewrite the Numbers**:
We can express 78 and 82 in terms of a base number. Here, we can use 80 as a base:
\[ 78 = 80 - 2 \quad \text{and} \quad 82 = 80 + 2 \]

2. **Apply the Difference of Squares Formula**:
The product can be rewritten using the difference of squares formula:
\[ (a - b)(a + b) = a^2 - b^2 \]
Here, \( a = 80 \) and \( b = 2 \). Thus, we have:
\[ 78 \times 82 = (80 - 2)(80 + 2) = 80^2 - 2^2 \]

3. **Calculate \( 80^2 \)**:
Now we calculate \( 80^2 \):
\[ 80^2 = 6400 \]

4. **Calculate \( 2^2 \)**:
Next, we calculate \( 2^2 \):
\[ 2^2 = 4 \]

5. **Subtract the Results**:
Now, we subtract \( 2^2 \) from \( 80^2 \):
\[ 6400 - 4 = 6396 \]

### Final Result:
Thus, the value of \( 78 \times 82 \) is:
\[ \boxed{6396} \]