Solve Vertical Subtraction: 85 minus 81 Step-by-Step

$\begin{aligned} &85 \\ -& \\ &81 \\ &\underline{\phantom{776}} & \\ \end{aligned}$

To solve this problem, we'll follow these steps:

• Step 1: Align the numbers for vertical subtraction.

• Step 2: Subtract the digits in the units column.

• Step 3: Subtract the digits in the tens column if necessary.

Now, let's work through each step:
Step 1: We'll arrange the numbers as follows:
$\begin{array}{c} {85} \\ {-81} ~~\ \\ \hline ? \\ \end{array}$ Step 2: Start by subtracting the digits in the units column: $5 - 1 = 4$.

Step 3: Move to the tens column: $8 - 8 = 0$.

The result is 04, which simplifies to just 4.

Therefore, the difference when we subtract 81 from 85 is $\boxed{4}$.