Long Addition Calculator

Step-by-step column addition for whole numbers and decimals with carry-over visualization

Calculate Long Addition

Enter a positive number (decimals allowed)

Enter a positive number (decimals allowed)

Example Calculation

Example 1: Whole Numbers

15292
+ 735
= 16027

Key steps: Handle carries when sum ≥ 10

Example 2: Decimal Numbers

4520.12
+ 535.90
= 5056.02

Key steps: Align decimal points, pad with zeros

Long Addition Rules

1

Align Numbers

Right-align by place value

Ones under ones, tens under tens

2

Add Columns

Start from rightmost column

Work left, one column at a time

3

Handle Carries

When sum ≥ 10, carry over

Write ones digit, carry tens digit

Addition Tips

Always align numbers by their rightmost digits

For decimals, align the decimal points

Remember to include carries in next column

Double-check by adding in reverse order

Understanding Long Addition (Column Addition)

What is Long Addition?

Long addition, also known as column addition, is a systematic method for adding numbers with multiple digits. It breaks down the addition into manageable steps by adding each column (place value) separately, starting from the rightmost column.

Why Use Long Addition?

  • Makes adding large numbers manageable
  • Reduces errors through systematic approach
  • Works for both whole numbers and decimals
  • Foundation for understanding place value

Step-by-Step Method

Step 1: Write numbers aligned by place value (right-aligned)
Step 2: Add the rightmost column first
Step 3: If sum ≥ 10, write ones digit and carry tens digit
Step 4: Move left, repeat for each column
Step 5: Include any carries in column calculations

Remember: For decimals, align decimal points and pad with zeros as needed.

Adding Decimal Numbers

When adding decimal numbers, the key is proper alignment. The decimal points must be aligned vertically, and you can fill in missing decimal places with zeros.

Example: 15.413 + 5437.321

Setup with alignment:
15.413
5437.321
────────
5452.734

Carrying Over Rules

Single Digit Sum (0-9):

Write the digit directly in the result

Two Digit Sum (10+):

Write ones digit in result, carry tens digit to next column

With Decimal Point:

Carry from after decimal to before decimal normally