Multi-Digit Addition
Once you can add two-digit numbers with carrying, the same method extends perfectly to any number of digits. The process never changes — you simply have more columns to work through.
Three-Digit Addition
Example: 456 + 387
¹ ¹ 4 5 6 + 3 8 7 ------- 8 4 3
Ones: 6+7=13 → 3 carry 1. Tens: 5+8+1=14 → 4 carry 1. Hundreds: 4+3+1=8. Answer: 843
Four-Digit Addition
Example: 3,742 + 1,589
¹ ¹
3 7 4 2
+ 1 5 8 9
---------
5 3 3 1
Ones: 2+9=11 → 1 carry 1. Tens: 4+8+1=13 → 3 carry 1. Hundreds: 7+5+1=13 → 3 carry 1. Thousands: 3+1+1=5. Answer: 5,331
Five-Digit Addition
Example: 24,567 + 38,946
¹ ¹ ¹ ¹ 2 4 5 6 7 + 3 8 9 4 6 ----------- 6 3 5 1 3
Ones: 7+6=13 → 3 carry 1. Tens: 6+4+1=11 → 1 carry 1. Hundreds: 5+9+1=15 → 5 carry 1. Thousands: 4+8+1=13 → 3 carry 1. Ten-thousands: 2+3+1=6. Answer: 63,513
Adding Three or More Numbers
Column addition handles three or more addends just as easily. Add all values in each column and carry if the total is 10 or more.
1,234 + 4,567 + 2,199 = ? → ones: 4+7+9=20 → 0 carry 2 → tens: 3+6+9+2=20 → 0 carry 2 → hundreds: 2+5+1+2=10 → 0 carry 1 → thousands: 1+4+2+1=8 → Answer: 8,000
Key Takeaways
- The column addition method works for any number of digits.
- Always align by place value and work right to left.
- When adding three or more numbers, a column can carry 2 or more.
- Estimate first (round to leading digits) to check your answer is reasonable.
Practice Questions
- Calculate 638 + 294.
- Calculate 4,851 + 2,769.
- Add 12,345 + 67,890.
- Calculate 5,678 + 3,456 + 2,789.
- A factory produces 12,450 items in January and 18,375 in February. What is the total output?