Solve Addition Problem: 855 + 117 in Vertical Format

Q: What does 'carry over' actually mean?

When adding digits gives you 10 or more, you write down the ones digit and add the tens digit to the next column. Like $5+7=12$ becomes write 2, carry 1!

Q: Why do I need to line up the numbers vertically?

Lining up by place value ensures you're adding units to units, tens to tens, and hundreds to hundreds. Misaligned numbers lead to completely wrong answers!

Q: Can I add from left to right instead?

You can, but it's harder because you might need to adjust previous digits when carrying. Right to left is the standard method because it handles carrying more naturally.

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

Add the numbers again using the same methodTry adding left to right: $800+100=900$, $50+10=60$, $5+7=12$, then $900+60+12=972$ ✓

Vertical Addition with Three-Digit Numbers

$\begin{aligned} &855 \\ +& \\ &117 \\ &\underline{\phantom{776}} & \\ \end{aligned}$

❤️ Continue Your Math Journey!

We have hundreds of course questions with personalized recommendations + Account 100% premium

Step-by-step video solution

Watch the teacher solve the problem with clear explanations

00:04 Let's solve this math problem together.

00:07 We'll add two digits at a time. Ready?

00:11 First, add the ones place. Here we go!

00:15 Add the ones, then carry over one to the tens column.

00:20 Now, let's add the tens. Don't forget to add the extra one.

00:25 Place the result in the tens spot.

00:29 Add the hundreds next. And place it in the hundreds column.

00:33 Great job! That's how we solve this problem.

Step-by-step written solution

Follow each step carefully to understand the complete solution

Understand the problem

$\begin{aligned} &855 \\ +& \\ &117 \\ &\underline{\phantom{776}} & \\ \end{aligned}$

Step-by-step solution

To solve this problem, we'll use vertical addition, a method of adding numbers by aligning them by their rightmost digits (unit place) and dealing with carrying as necessary:

Step 1: Align the numbers by place value:
$\phantom{+}855 \\$ + $\phantom{+}117$
Step 2: Add the digits in the unit's place:
The digits in the unit's place are $5$ and $7$ . Adding them gives $12$ . Write down $2$ in the unit column and carry over $1$ to the tens column.
Step 3: Add the digits in the ten's place:
The digits in the ten's place are $5$ and $1$ , plus the carried over $1$ , giving us $7$ . Write $7$ in the tens column.
Step 4: Add the digits in the hundred's place:
The digits in the hundred's place are $8$ and $1$ . Adding them gives $9$ .

Summing these gives us the total:
$\phantom{+}855 \\$ + $\phantom{+}117 \\$ \underline{\phantom{.}972} \)

Thus, the answer is $972$ .

Final Answer

972

Key Points to Remember

Essential concepts to master this topic

Alignment: Line up digits by place value columns correctly
Carrying: Write 5+7=12 as 2, carry 1 to tens place
Verification: Check by adding left to right: 800+50+5+100+10+7=972 ✓

Common Mistakes

Avoid these frequent errors

Forgetting to carry over when sum exceeds 9
Don't write 12 in the units place when 5+7=12! This creates impossible digits and wrong totals. Always write the ones digit (2) and carry the tens digit (1) to the next column.

Practice Quiz

Test your knowledge with interactive questions

$\begin{aligned} &12 \\ +& \\ &~~2 \\ &\underline{\phantom{776}} & \\ \end{aligned}$

FAQ

Everything you need to know about this question

What does 'carry over' actually mean?

When adding digits gives you 10 or more, you write down the ones digit and add the tens digit to the next column. Like $5+7=12$ becomes write 2, carry 1!

Why do I need to line up the numbers vertically?

Lining up by place value ensures you're adding units to units, tens to tens, and hundreds to hundreds. Misaligned numbers lead to completely wrong answers!

What if I forget to add the carried number?

Your answer will be wrong! In this problem, forgetting the carried 1 in the tens place would give $962$ instead of $972$ . Always remember carried digits.

Can I add from left to right instead?

You can, but it's harder because you might need to adjust previous digits when carrying. Right to left is the standard method because it handles carrying more naturally.

How do I check if my answer is correct?

Add the numbers again using the same method
Try adding left to right: $800+100=900$ , $50+10=60$ , $5+7=12$ , then $900+60+12=972$ ✓

What if there are more than two numbers to add?

Same process! Line them up, add column by column from right to left, and carry over whenever a column sum is 10 or more. Just take your time with each step.

🌟 Unlock Your Math Potential

Get unlimited access to all 18 Arithmetic Operations questions, detailed video solutions, and personalized progress tracking.

📹

Unlimited Video Solutions

Step-by-step explanations for every problem

📊

Progress Analytics

Track your mastery across all topics

🚫

Ad-Free Learning

Focus on math without distractions

No credit card required • Cancel anytime