Solve the Decimal Addition: 0.4 + 0.3

Q: Why can't I just add 4 + 3 = 7 and call it done?

Because 0.4 means 4 tenths, not 4 ones! When you ignore the decimal point, you're adding completely different values. Always keep the decimal point in the correct position.

Q: How do I know where to put the decimal point in my answer?

The decimal point in your answer goes in the same column as the decimal points in the numbers you're adding. Just draw a straight line down!

Q: What if I get confused about place values?

Remember: the first digit after the decimal point is tenths, the second is hundredths. So $ 0.4 $ = 4 tenths and $ 0.3 $ = 3 tenths.

Q: Is there a way to check my decimal addition?

Yes! Convert to fractions: $ 0.4 = \frac{4}{10} $ and $ 0.3 = \frac{3}{10} $, so $ \frac{4}{10} + \frac{3}{10} = \frac{7}{10} = 0.7 $ ✓

Decimal Addition with Tenths Place

Solve the following:

$0.4+0.3=$

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Step-by-step video solution

Watch the teacher solve the problem with clear explanations

00:05 Let's solve this by adding vertically.

00:09 First, arrange the numbers one below the other.

00:13 Make sure the decimal points line up nicely.

00:16 Start with the smallest digits on the right.

00:20 Add them up and write the result.

00:25 Keep going, add the next digits, and write each total.

00:34 That's how you find the answer! Well done!

Step-by-step written solution

Follow each step carefully to understand the complete solution

Understand the problem

Solve the following:

$0.4+0.3=$

Step-by-step solution

To solve the decimal addition $0.4 + 0.3$ , we will follow these steps:

Step 1: Line up the numbers by the decimal point.
Step 2: Add the decimal fractions directly as both numbers have only one digit after the decimal point.
Step 3: Sum the values and retain the decimal point in the same position for the result.

Let's begin the calculation:

Write the numbers aligning them by the decimal point:

$0.4$
$+0.3$
_______
$0.7$

Adding the two numbers $0.4$ and $0.3$ gives $0.7$ .

Therefore, the solution to the problem is $0.7$ , which matches choice 1.

Final Answer

0.7

Key Points to Remember

Essential concepts to master this topic

Alignment Rule: Line up decimal points vertically before adding
Technique: Add digits in same place value: 4 tenths + 3 tenths = 7 tenths
Check: Result should have decimal point in same position: $0.4 + 0.3 = 0.7$ ✓

Common Mistakes

Avoid these frequent errors

Adding digits without aligning decimal points
Don't just add 4 + 3 = 7 and place decimal randomly! This ignores place value and gives wrong answers like 7 or 0.43. Always align decimal points first, then add column by column from right to left.

Practice Quiz

Test your knowledge with interactive questions

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FAQ

Everything you need to know about this question

Why can't I just add 4 + 3 = 7 and call it done?

Because 0.4 means 4 tenths, not 4 ones! When you ignore the decimal point, you're adding completely different values. Always keep the decimal point in the correct position.

Do I need to write 0.4 as 0.40 to add it?

Not necessary! Since both numbers have the same number of decimal places (one digit after the point), you can add them directly. Adding zeros doesn't change the value: $0.4 = 0.40$ .

How do I know where to put the decimal point in my answer?

The decimal point in your answer goes in the same column as the decimal points in the numbers you're adding. Just draw a straight line down!

What if I get confused about place values?

Remember: the first digit after the decimal point is tenths, the second is hundredths. So $0.4$ = 4 tenths and $0.3$ = 3 tenths.

Is there a way to check my decimal addition?

Yes! Convert to fractions: $0.4 = \frac{4}{10}$ and $0.3 = \frac{3}{10}$ , so $\frac{4}{10} + \frac{3}{10} = \frac{7}{10} = 0.7$ ✓

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