Solve Decimal Subtraction: 6.8 - 4.2

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

• Step 1: Align the numbers by their decimal points.
• Step 2: Subtract the subtrahend from the minuend.
• Step 3: Place the decimal point in the answer, directly aligned with the decimal points of the numbers.

Now, let's work through each step:
Step 1: Align the numbers, $6.8$ and $4.2$, by their decimal points:

$6.8$
$-4.2$
$\underline{\phantom{9.9}}$

Step 2: Subtract each digit starting from the rightmost end (tenths place). Subtract $2$ from $8$ to get $6$.
Then subtract $4$ from $6$ to get $2$.

$6.8$
$-4.2$
$\underline{2.6}$

Step 3: Make sure to align the decimal point in the answer with the other decimal points. The result is $2.6$.

Therefore, the solution to the problem is $2.6$.