Complete the Decimal Expression: 3.1 = ?

Q: How do I know what denominator to use for the fraction?

Look at the place value of the decimal digit! The digit 1 in $ 3.1 $ is in the tenths place, so the denominator is 10.

Q: What if the decimal has more digits like 3.25?

Count the decimal places! $ 3.25 $ has 2 decimal places, so it becomes $ 3\frac{25}{100} = 3\frac{1}{4} $ after simplifying.

Q: Do I always need to simplify the fraction part?

Yes, when possible! $ \frac{25}{100} $ simplifies to $ \frac{1}{4} $, but $ \frac{1}{10} $ is already in lowest terms.

Q: Can I convert back to check my answer?

Absolutely! Convert your mixed number back to decimal: $ 3\frac{1}{10} = 3 + \frac{1}{10} = 3 + 0.1 = 3.1 $. Perfect match!

Q: What if I see 3.10 instead of 3.1?

They're the same! $ 3.1 = 3.10 $ because trailing zeros don't change the value. Both equal $ 3\frac{1}{10} $.

Decimal to Mixed Number Conversion

$3.1=$

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Step-by-step video solution

Watch the teacher solve the problem with clear explanations

00:02 Let's convert the improper fraction into a mixed number.

00:06 First, separate the whole number part from the remainder.

00:11 Next, take the remainder and turn it into a fraction.

00:16 Now, put it all together to form your mixed number.

00:20 And that's how you solve this problem!

Step-by-step written solution

Follow each step carefully to understand the complete solution

Understand the problem

$3.1=$

Step-by-step solution

To solve this problem, we need to convert the decimal $3.1$ into a mixed number:

Step 1: Recognize the decimal number $3.1$ consists of a whole number part $3$ and a decimal part $0.1$ .
Step 2: Convert the decimal part $0.1$ to a fraction. The decimal $0.1$ is equivalent to $\frac{1}{10}$ .
Step 3: Combine the whole number part with the fractional part to form the mixed number, which gives us $3\frac{1}{10}$ .

Therefore, the decimal $3.1$ is equivalent to the mixed number $3\frac{1}{10}$ .

The correct choice is option 1: $3\frac{1}{10}$ .

Final Answer

$3\frac{1}{10}$

Key Points to Remember

Essential concepts to master this topic

Rule: Decimal parts become fractions with powers of 10
Technique: $0.1 = \frac{1}{10}$ because 1 is in tenths place
Check: Convert back: $3\frac{1}{10} = 3 + 0.1 = 3.1$ ✓

Common Mistakes

Avoid these frequent errors

Confusing decimal place values with fraction denominators
Don't write $0.1 = \frac{1}{1}$ or guess random denominators = wrong fractions! The decimal 0.1 means 1 tenth, not 1 whole. Always use the place value: tenths place means denominator 10.

Practice Quiz

Test your knowledge with interactive questions

Write the following fraction as a decimal:

$\frac{5}{100}=$

FAQ

Everything you need to know about this question

How do I know what denominator to use for the fraction?

Look at the place value of the decimal digit! The digit 1 in $3.1$ is in the tenths place, so the denominator is 10.

What if the decimal has more digits like 3.25?

Count the decimal places! $3.25$ has 2 decimal places, so it becomes $3\frac{25}{100} = 3\frac{1}{4}$ after simplifying.

Do I always need to simplify the fraction part?

Yes, when possible! $\frac{25}{100}$ simplifies to $\frac{1}{4}$ , but $\frac{1}{10}$ is already in lowest terms.

Can I convert back to check my answer?

Absolutely! Convert your mixed number back to decimal: $3\frac{1}{10} = 3 + \frac{1}{10} = 3 + 0.1 = 3.1$ . Perfect match!

What if I see 3.10 instead of 3.1?

They're the same! $3.1 = 3.10$ because trailing zeros don't change the value. Both equal $3\frac{1}{10}$ .

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