Solve Decimal Subtraction: 27.4 - 10.5 Step-by-Step

Q: Why can't I just subtract 4 - 5 in the tenths place?

You can't subtract a larger digit from a smaller one directly. When 4 - 5 is impossible, you need to borrow from the next column to the left, making it 14 - 5 = 9.

Q: What happens to the number I borrowed from?

When you borrow 1 from the ones place, 7 becomes 6 in $ 27.4 $. The borrowed 1 moves to the tenths place, making 4 become 14.

Q: How do I know when to borrow in decimal subtraction?

Borrow whenever the top digit is smaller than the bottom digit in any column. It works the same way as whole number subtraction, just with decimal places!

Q: Can I add zeros to make the numbers the same length?

Yes! You can write $ 10.5 $ as $ 10.50 $ to help with alignment. Adding zeros to the right of the decimal doesn't change the value.

Q: How can I check if my answer is correct?

Use addition to check subtraction! Add your answer to the number you subtracted: $ 16.9 + 10.5 = 27.4 $ ✓

Q: What if I get confused with all the borrowing steps?

Take it one column at a time from right to left. Write down each step clearly and don't rush. Practice makes perfect with borrowing!

Decimal Subtraction with Borrowing Technique

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Step-by-step video solution

Watch the teacher solve the problem with clear explanations

00:00 Solve

00:03 We'll start subtracting from right to left

00:06 The digit is too small for subtraction, so we'll borrow from the next one

00:09 The next digit will decrease by 1, and our digit will increase by 10

00:13 Now we'll subtract from the larger number

00:18 We'll calculate and substitute accordingly

00:26 We'll continue to subtract, calculate and substitute accordingly

00:44 And this is the solution to the question

Step-by-step written solution

Follow each step carefully to understand the complete solution

Understand the problem

Step-by-step solution

Let's solve the subtraction problem $27.4 - 10.5$ step-by-step:

Step 1: Align the numbers vertically by the decimal point:

$\begin{aligned} 27.4 \\ -10.5 \\ \hline \end{aligned}$

Step 2: Start subtracting from the rightmost digit, moving to the left.

In the tenths column (4 - 5), we need to borrow from the ones column.
Borrowing 1 from the ones column changes 27.4 to 26.14:

$\begin{aligned} 26.14 \\ -10.50 \\ \hline \end{aligned}$

Now subtract the tenths: 14 - 5 = 9.
Next, subtract the ones column: 6 - 0 = 6.
Finally, subtract the tens column: 2 - 1 = 1.

Therefore, the result of $27.4 - 10.5$ is $16.9$ .

The correct answer is $\boxed{16.9}$ .

Final Answer

16.9

Key Points to Remember

Essential concepts to master this topic

Alignment Rule: Always align decimal points vertically before subtracting
Borrowing Technique: Convert 27.4 to 26.14 when borrowing from ones place
Verification: Check that 16.9 + 10.5 = 27.4 to confirm answer ✓

Common Mistakes

Avoid these frequent errors

Not aligning decimal points properly
Don't line up digits from the right side like whole numbers = wrong place values! This creates errors like getting 17.9 instead of 16.9. Always align the decimal points first, then work column by column.

Practice Quiz

Test your knowledge with interactive questions

$\text{0.6+0}.5=$

FAQ

Everything you need to know about this question

Why can't I just subtract 4 - 5 in the tenths place?

You can't subtract a larger digit from a smaller one directly. When 4 - 5 is impossible, you need to borrow from the next column to the left, making it 14 - 5 = 9.

What happens to the number I borrowed from?

When you borrow 1 from the ones place, 7 becomes 6 in $27.4$ . The borrowed 1 moves to the tenths place, making 4 become 14.

How do I know when to borrow in decimal subtraction?

Borrow whenever the top digit is smaller than the bottom digit in any column. It works the same way as whole number subtraction, just with decimal places!

Can I add zeros to make the numbers the same length?

Yes! You can write $10.5$ as $10.50$ to help with alignment. Adding zeros to the right of the decimal doesn't change the value.

How can I check if my answer is correct?

Use addition to check subtraction! Add your answer to the number you subtracted: $16.9 + 10.5 = 27.4$ ✓

What if I get confused with all the borrowing steps?

Take it one column at a time from right to left. Write down each step clearly and don't rush. Practice makes perfect with borrowing!

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