Solve Decimal Addition: 0.77 + 30.6 in Vertical Format

To solve this problem, follow these steps:

• Step 1: Align the numbers $0.77$ and $30.6$ by their decimal points:
  $\begin{aligned} 30&.6 \\ + ~~ 0&.77 \\ \hline \end{aligned}$

• Step 2: Add these numbers starting from the rightmost digit, considering each place value.

• Adding hundredths place:
  $0 + 7 = 7$

• Adding tenths place:
  $6 + 7 = 13$, write down $3$ and carry over 1 to the next column.

• Adding whole number and carry over:
  $0 + 1 + 30 = 31$

• Thus, the sum is $31.37$.

Therefore, the solution to the problem is $31.37$.