Solve for the Missing Addend in 5.8 + ? = 9.9

Video Solution

Solution Steps

00:00 Identify which of the following answers is correct

00:03 Insert each of the potential answers into the expression in order to verify which of them is correct

00:11 Use vertical addition for the calculation

00:16 Insert one of the potential answers into the expression and proceed to calculate

00:37 We can see that the first option is not suitable, let's move on to the second one

00:42 Let's apply the same method as before and proceed to check

00:51 Insert another one of the answers into the expression and proceed to check it

01:04 We can see that the second option is suitable, let's now move on to the third one

01:10 Once again apply the same method as before and proceed to check

01:20 Insert one of the remaining answers into the expression and calculate

01:46 We can see that the third option is not suitable, let's move on to the fourth one:

01:56 Apply the same method as before and proceed to check

02:04 Insert the remaining answer into the expression and proceed to calculate

02:25 We can see that the fourth option is not suitable

02:30 This is the solution

Step-by-Step Solution

To solve this problem, we need to determine the missing value in the equation $5.8 + ? = 9.9$ .

First, let's isolate the unknown value by rearranging the equation. We know that $? = 9.9 - 5.8$ .
Next, perform the subtraction: $9.9 - 5.8$ .

Let's calculate:

Align the decimal places and subtract:

  9.9
- 5.8
-----
  4.1

The result of $9.9 - 5.8$ is $4.1$ .

Therefore, the missing value is $4.1$ . Hence, the equation becomes $5.8 + 4.1 = 9.9$ .

Therefore, the correct answer is option 2: 4.1.