Solve the Decimal Equation: Finding the Number in x - 0.8 = 0.1

Let's solve the equation $? - 0.8 = 0.1$ by isolating the unknown variable:

Step 1: Write the equation:

$? - 0.8 = 0.1$

Step 2: To find the value of '?', add $0.8$ to both sides of the equation as follows:

$? - 0.8 + 0.8 = 0.1 + 0.8$

Step 3: Simplify both sides:

The left side simplifies to $?$ because $-0.8 + 0.8 = 0$.

The right side becomes $0.1 + 0.8 = 0.9$.

So, $? = 0.9$.

Therefore, the missing value is $0.9$.