To solve the equation \( 4.72(x - 6.56) = 10.4 \), the first step is indeed to divide both sides by \( 4.72 \).
So, you divide:
\[ x - 6.56 = \frac{10.4}{4.72} \]
Calculating the right side:
\[ \frac{10.4}{4.72} \approx 2.207 \]
After this division, the equation simplifies to:
\[ x - 6.56 \approx 2.207 \]
Next, to isolate \( x \), you need to add \( 6.56 \) to both sides:
\[ x \approx 2.207 + 6.56 \]
So, the number that should be added to both sides is \( 6.56 \).