Solve the Decimal Equation: Finding the Missing Value in 0.4 - ? = 0.2

To solve this problem, we'll find the missing value using simple subtraction as follows:

• Step 1: Identify the equation given: $0.4 - ? = 0.2$.
• Step 2: Rearrange the equation to solve for ?:
  $? = 0.4 - 0.2$
• Step 3: Perform the subtraction:
  $0.4 - 0.2 = 0.2$
• The missing value that satisfies the equation is $0.2$.

From the choices provided, the correct answer is choice 2: 0.2.