Calculate 505 - 20.3: Decimal Subtraction in Vertical Format

To solve this problem, we'll perform the subtraction $505 - 20.3$ step by step:

• Step 1: Align the numbers
  Write $505.0$ with a zero added in the tenths place for alignment:
  $\begin{array}{c} 505.0 \\ - 20.3 \\ \hline \end{array}$
• Step 2: Perform the subtraction
  Start from the rightmost digit:
  • Tenths column: $0 - 3$ cannot be done directly, so we borrow 1 from the units column, making it $10 - 3 = 7$.
  • Units column: Now $5 - 2 = 3$, after borrowing $1$.
  • Tens column: $10 - 2 = 8$ because we've borrowed 1 earlier adding to the initial 0, leaving the column value as 4 from the hundreds place.
  • Hundreds column: $4 - 0 = 4$, after handling the earlier borrow.

After calculating, the result of $505 - 20.3$ is therefore:

$484.7$

Thus, the solution to the problem is $484.7$.