Solve for the Missing Number: ? + 3.3 = 6.7

Q: Why do I subtract 3.3 from 6.7 instead of adding?

Because subtraction is the inverse of addition! When you have ? + 3.3 = 6.7, you need to 'undo' the +3.3 by subtracting it from both sides.

Q: How do I line up decimal numbers when subtracting?

Always line up the decimal points vertically! Write 6.7 above 3.3 with the decimal points in the same column, then subtract normally.

Q: What if I get a different decimal answer?

Double-check your subtraction! Make sure you borrowed correctly if needed. Remember: 6.7 - 3.3 should give you 3.4, not 3.1, 3.2, or 3.3.

Q: Can I check my answer without substituting back?

Yes! You can add your answer to 3.3: $ 3.4 + 3.3 = 6.7 $. If you get 6.7, your answer is correct!

Q: Why are the other answer choices close to 3.4?

The wrong answers test common decimal subtraction errors! They're designed to catch mistakes like not borrowing properly or misaligning decimal places.

Decimal Addition with Missing Addends

Fill in the missing value (?):

$?+3.3=6.7$

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Step-by-step video solution

Watch the teacher solve the problem with clear explanations

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

00:07 Use vertical addition to calculate the problem

00:11 Insert one of the answers into the expression and proceed to calculate

00:27 We can see that the first option doesn't fit, let's move on to the second one

00:35 Let's apply the same method as before and proceed to check

00:41 Insert one of the answers into the expression and calculate

00:54 We can see that the second option doesn't fit, let's move on to the third one:

01:03 Once again apply the same method as before and proceed to check

01:10 Insert one of the remaining answers into the expression and calculate

01:24 We can see that the third option doesn't fit, let's move on to the fourth and final one:

01:33 Apply the same method as before and proceed to check

01:41 Insert the remaining answer into the expression and calculate

01:55 We can see that the fourth option fits

02:01 This is the solution

Step-by-step written solution

Follow each step carefully to understand the complete solution

Understand the problem

Fill in the missing value (?):

$?+3.3=6.7$

Step-by-step solution

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

Step 1: Understand the equation $? + 3.3 = 6.7$ .
Step 2: Rewrite the equation to solve for the missing value as $? = 6.7 - 3.3$ .
Step 3: Perform the subtraction to find the value of ?.

Begin by setting up the equation:
$\, ? + 3.3 = 6.7$
To solve for $?$ , we rearrange the equation: $? = 6.7 - 3.3$

Perform the subtraction:
$6.7 - 3.3 = 3.4$

Thus, the missing value is 3.4. Hence, $? = 3.4$ .

Therefore, the correct choice from the given options is choice 4: 3.4, which matches our calculated result.

Final Answer

3.4

Key Points to Remember

Essential concepts to master this topic

Inverse Operation: To find missing addend, subtract from the sum
Technique: Rearrange ? + 3.3 = 6.7 to ? = 6.7 - 3.3
Check: Substitute back: 3.4 + 3.3 = 6.7 ✓

Common Mistakes

Avoid these frequent errors

Adding 3.3 to 6.7 instead of subtracting
Don't add 3.3 + 6.7 = 10.0! This gives the wrong operation because you need to undo the addition. Always subtract the known addend from the sum to find the missing addend.

Practice Quiz

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FAQ

Everything you need to know about this question

Why do I subtract 3.3 from 6.7 instead of adding?

Because subtraction is the inverse of addition! When you have ? + 3.3 = 6.7, you need to 'undo' the +3.3 by subtracting it from both sides.

How do I line up decimal numbers when subtracting?

Always line up the decimal points vertically! Write 6.7 above 3.3 with the decimal points in the same column, then subtract normally.

What if I get a different decimal answer?

Double-check your subtraction! Make sure you borrowed correctly if needed. Remember: 6.7 - 3.3 should give you 3.4, not 3.1, 3.2, or 3.3.

Can I check my answer without substituting back?

Yes! You can add your answer to 3.3: $3.4 + 3.3 = 6.7$ . If you get 6.7, your answer is correct!

Why are the other answer choices close to 3.4?

The wrong answers test common decimal subtraction errors! They're designed to catch mistakes like not borrowing properly or misaligning decimal places.

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