Solve Vertical Addition: Adding 100 + 5 Step by Step

Q: Why does 5 go under the ones place and not the hundreds place?

Because 5 represents 5 ones, not 5 hundreds! In place value, each digit has a specific position. The number 5 means 5 ones, so it must line up with the ones column of 100.

Q: How do I remember which column to start adding from?

Always start from the right (ones place) and work left! This follows the same pattern as regular addition and helps you handle any carrying that might be needed in harder problems.

Q: Is there a quick way to check if 105 is right?

Yes! Use mental math: 100 + 5 = 105. You can also count up from 100 five times, or use a number line to verify your answer makes sense.

Vertical Addition with Place Value Alignment

$\begin{aligned} &100 \\ +& \\ &~~~~5 \\ &\underline{\phantom{776}} & \\ \end{aligned}$

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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 we'll calculate the sum of 2 digits, and then substitute

00:06 Let's start by adding ones with ones

00:09 Put 0 in the missing digits

00:12 Add the tens, and substitute in tens place

00:15 Put 0 in the missing digits

00:19 Add the hundreds, and substitute in hundreds place

00:22 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

$\begin{aligned} &100 \\ +& \\ &~~~~5 \\ &\underline{\phantom{776}} & \\ \end{aligned}$

Step-by-step solution

To solve this problem, we will use vertical addition.

Let's perform the steps:

Step 1: Write the numbers 100 and 5 vertically, aligning them by place value. Since 5 is a single-digit number, it will align under the ones place of 100. This gives us:

$\begin{aligned} &100 \\ +& \\ &~~5 \\ \end{aligned}$
Step 2: Add the numbers column by column, starting from the right.
- Add the ones place: $0 + 5 = 5$
- Add the tens place: $0 + 0 = 0$
- Add the hundreds place: $1 + 0 = 1$
This results in a sum of $105$ .

Therefore, the solution to the problem is $105$ .

Final Answer

105

Key Points to Remember

Essential concepts to master this topic

Alignment: Line up numbers by place value columns correctly
Technique: Add column by column from right: 0+5=5, 0+0=0, 1+0=1
Check: Verify by counting up from 100: 101, 102, 103, 104, 105 ✓

Common Mistakes

Avoid these frequent errors

Misaligning place values when setting up the problem
Don't write 5 under the hundreds place of 100 = wrong column addition! This makes you add 5 to 1 instead of 0, giving 600 instead of 105. Always align single-digit numbers under the ones place column.

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 does 5 go under the ones place and not the hundreds place?

Because 5 represents 5 ones, not 5 hundreds! In place value, each digit has a specific position. The number 5 means 5 ones, so it must line up with the ones column of 100.

What if I accidentally put 5 under the wrong column?

You'll get the wrong answer! If 5 goes under the hundreds place, you'd be adding $100 + 500 = 600$ instead of $100 + 5 = 105$ . Always double-check your alignment before adding.

Do I need to write zeros in empty spaces?

It helps for clarity! You can think of 5 as 005 to see it has 0 hundreds, 0 tens, and 5 ones. This makes alignment easier: line up matching place values.

How do I remember which column to start adding from?

Always start from the right (ones place) and work left! This follows the same pattern as regular addition and helps you handle any carrying that might be needed in harder problems.

Is there a quick way to check if 105 is right?

Yes! Use mental math: 100 + 5 = 105. You can also count up from 100 five times, or use a number line to verify your answer makes sense.

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