Solve Vertical Addition: 27 + 85 Step-by-Step

Q: Why do we start adding from the right side?

We start with the ones place (rightmost column) because any carrying affects the next column to the left. If we started from the left, we'd have to redo our work when we discover carries!

Q: What does it mean to 'carry over'?

Carrying means moving the tens digit to the next column when a sum is 10 or more. For example, $ 7 + 5 = 12 $ means write 2 and carry the 1 to the tens place.

Q: How do I know if I carried correctly?

Check that each column sum makes sense: ones place should be a single digit, and any carried number gets added to the next column. Your final answer should match mental math estimates.

Q: Can I add the numbers in any order?

Yes! Addition is commutative, so 27 + 85 equals 85 + 27. However, keep the vertical alignment the same to avoid place value errors.

Q: What if I get confused about which number to carry?

Always carry the tens digit of any sum that's 10 or greater. So if a column adds to 15, carry the 1 and write down the 5. Practice with smaller numbers first!

Vertical Addition with Carrying

$\begin{aligned} &27 \\ +& \\ &85 \\ &\underline{\phantom{776}} & \\ \end{aligned}$

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Step-by-step video solution

Watch the teacher solve the problem with clear explanations

00:00 Solve

00:03 Each time consider combining 2 digits, and then write

00:06 Start by adding ones with ones

00:09 Write down the ones, and remember 1 to carry up

00:12 Add tens with tens, remember to add 1 to the calculation

00:19 Write down the tens in the tens place, and carry 1 to hundreds

00:23 Write 0 in the missing digits

00:29 Add hundreds with hundreds, and write in the appropriate position

00:32 And this is the solution to the problem

Step-by-step written solution

Follow each step carefully to understand the complete solution

Understand the problem

$\begin{aligned} &27 \\ +& \\ &85 \\ &\underline{\phantom{776}} & \\ \end{aligned}$

Step-by-step solution

To solve this problem, we'll follow the standard procedure for vertical addition:

Step 1: Write the numbers vertically, aligning by place value. Here, we have:
$27$

$+85$
Step 2: Add the digits in the units place (rightmost column).
$7 + 5 = 12$
Since 12 is 10 or more, we write down 2 in the units place and carry over 1 to the tens place.
Step 3: Move to the tens place and add the digits, including the carryover from the previous step.
$2 + 8 + 1 = 11$
Write down 11 in the tens place, as there are no more numbers to add.

Therefore, the sum is $112$ .

The correct answer is choice 3: 112.

Final Answer

112

Key Points to Remember

Essential concepts to master this topic

Place Value Alignment: Line up ones under ones, tens under tens
Carrying Technique: When 7 + 5 = 12, write 2 and carry 1
Check: Add horizontally to verify: 20 + 7 + 80 + 5 = 112 ✓

Common Mistakes

Avoid these frequent errors

Forgetting to carry over when sum exceeds 9
Don't just write down 12 in the ones place = wrong place values! This creates numbers like 2712 instead of 112. Always carry the tens digit to the next column when any column sum is 10 or greater.

Practice Quiz

Test your knowledge with interactive questions

$\begin{aligned} &90 \\ +& \\ &~~9\\ &\underline{\phantom{776}} & \\ \end{aligned}$

FAQ

Everything you need to know about this question

Why do we start adding from the right side?

We start with the ones place (rightmost column) because any carrying affects the next column to the left. If we started from the left, we'd have to redo our work when we discover carries!

What does it mean to 'carry over'?

Carrying means moving the tens digit to the next column when a sum is 10 or more. For example, $7 + 5 = 12$ means write 2 and carry the 1 to the tens place.

How do I know if I carried correctly?

Check that each column sum makes sense: ones place should be a single digit, and any carried number gets added to the next column. Your final answer should match mental math estimates.

Can I add the numbers in any order?

Yes! Addition is commutative, so 27 + 85 equals 85 + 27. However, keep the vertical alignment the same to avoid place value errors.

What if I get confused about which number to carry?

Always carry the tens digit of any sum that's 10 or greater. So if a column adds to 15, carry the 1 and write down the 5. Practice with smaller numbers first!

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