Solve Decimal Subtraction: 0.4 - 0.2 Step-by-Step

Q: Why do I need to align the decimal points?

Aligning decimal points ensures you're subtracting like place values - tenths from tenths, hundredths from hundredths. Without alignment, you might subtract different place values and get wrong answers!

Q: What if the decimals have different numbers of digits?

Add zeros as placeholders to make them the same length. For example, treat 0.4 as 0.40 when subtracting from a hundredths decimal.

Q: How do I know my decimal answer is in the right place?

The decimal point in your answer should be directly below the decimal points in the problem. Count the decimal places - they should match!

Q: Can I check my decimal subtraction?

Yes! Add your answer to the number you subtracted: $ 0.2 + 0.2 = 0.4 $. If you get the original number, you're correct!

Q: What if I get confused about place values?

Remember: the first digit after the decimal is tenths, the second is hundredths. Say the place values out loud as you work!

Decimal Subtraction with Tenths Place

$\text{0}.4-0.2=$

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Step-by-step video solution

Watch the teacher solve the problem with clear explanations

00:04 Let's solve this problem together!

00:07 We'll use long subtraction to find the answer.

00:12 First, make sure to place the decimal point correctly.

00:16 Now, begin subtracting from the smallest digits.

00:19 Keep subtracting and calculating carefully.

00:23 And there you have it, that's the solution!

Step-by-step written solution

Follow each step carefully to understand the complete solution

Understand the problem

$\text{0}.4-0.2=$

Step-by-step solution

To solve this problem, let's perform the following steps:

Step 1: Write the numbers vertically, aligning the decimal points.
Step 2: Subtract as you would with whole numbers, starting from the right.
Step 3: Bring down the decimal point in the same position below the numbers being subtracted.

Now, applying these steps to $0.4 - 0.2$ :

0.4
− 0.2

Subtract the numbers in the tenths place:

4 - 2 = 2

So, the result of $0.4 - 0.2$ is $0.2$ .

In this problem, the correct answer from the provided choices is 0.2.

Final Answer

0.2

Key Points to Remember

Essential concepts to master this topic

Rule: Align decimal points vertically before subtracting
Technique: Subtract tenths place: 4 - 2 = 2 tenths
Check: Add result back: 0.2 + 0.2 = 0.4 ✓

Common Mistakes

Avoid these frequent errors

Subtracting without aligning decimal points
Don't subtract 4 - 2 = 2 as whole numbers! This gives wrong place values and incorrect answers like 2 instead of 0.2. Always align decimal points vertically first.

Practice Quiz

Test your knowledge with interactive questions

Determine whether the exercise is written correctly in relation to the position of the decimal point:

FAQ

Everything you need to know about this question

Why do I need to align the decimal points?

Aligning decimal points ensures you're subtracting like place values - tenths from tenths, hundredths from hundredths. Without alignment, you might subtract different place values and get wrong answers!

What if the decimals have different numbers of digits?

Add zeros as placeholders to make them the same length. For example, treat 0.4 as 0.40 when subtracting from a hundredths decimal.

How do I know my decimal answer is in the right place?

The decimal point in your answer should be directly below the decimal points in the problem. Count the decimal places - they should match!

Can I check my decimal subtraction?

Yes! Add your answer to the number you subtracted: $0.2 + 0.2 = 0.4$ . If you get the original number, you're correct!

What if I get confused about place values?

Remember: the first digit after the decimal is tenths, the second is hundredths. Say the place values out loud as you work!

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