Solve for the Missing Addend: 0.4 + ? = 0.9

To solve the problem of finding the missing value $?$ in the equation $0.4 + ? = 0.9$, we'll perform the following steps:

• Step 1: Identify what is given and what is missing in the equation.
• Step 2: Use subtraction to isolate the missing value.
• Step 3: Execute the subtraction and find the missing value.

Now, let's proceed through these steps in detail:

Step 1: The equation given is $0.4 + ? = 0.9$. Here, the goal is to identify the number, represented by $?$, which when added to $0.4$ equals $0.9$.

Step 2: To find $?$, we need to isolate it. We can do this by subtracting $0.4$ from both sides of the equation:

$? = 0.9 - 0.4$

Step 3: Calculate the result of the subtraction:

$? = 0.9 - 0.4 = 0.5$

Therefore, the missing value $?$ that satisfies the equation $0.4 + ? = 0.9$ is $0.5$.

Let's confirm this with the multiple choice provided: the correct answer is choice :

0.5

.