Steps to Adding Numbers Without a Calculator
- Stack the numbers on top of each other with like places and decimal points vertically aligned.
- Start in the right-most column and work from right to left.
- Add the column's numbers together, including any carryover, to get the column sum.
- If the column sum is less than 10, place the sum beneath the column.
- If the column sum is greater than 10, enter the ones place of the column sum beneath the column and carry the remaining places to the top of the next column.
- Repeat steps 3-5 for the remainder of the columns.
Here is a step-by-step example of how to add the following numbers:
| 123.4 |
| 5.67 |
| 8910 |
Stack the numbers on top of each other so that all places are aligned (red vertical line indicates where the decimal points are located).
| col # | 1 | 2 | 3 | 4 | 5 | 6 |
| carry | ||||||
| + | 1 | 2 | 3 | 4 | 0 | |
| 5 | 6 | 7 | ||||
| 8 | 9 | 1 | 0 | 0 | 0 | |
| sum |
Starting from the right-most column and moving from right to left, add the numbers and any carryover in each column.
Column #6 (Hundredths place) Steps:
0 + 7 + 0 = 7
Enter the 7 in the sum row of column #6
0 + 7 + 0 = 7
Enter the 7 in the sum row of column #6
| col # | 1 | 2 | 3 | 4 | 5 | 6 |
| carry | ||||||
| + | 1 | 2 | 3 | 4 | 0 | |
| 5 | 6 | 7 | ||||
| 8 | 9 | 1 | 0 | 0 | 0 | |
| sum | 7 |
Column #5 (Tenths place) Steps:
4 + 6 + 0 = 10
Enter the 0 in the sum row of column #5
Carry the 1 to the top of column #4
4 + 6 + 0 = 10
Enter the 0 in the sum row of column #5
Carry the 1 to the top of column #4
| col # | 1 | 2 | 3 | 4 | 5 | 6 |
| carry | 1 | |||||
| + | 1 | 2 | 3 | 4 | 0 | |
| 5 | 6 | 7 | ||||
| 8 | 9 | 1 | 0 | 0 | 0 | |
| sum | 0 | 7 |
Column #4 (Ones place) Steps:
1 + 3 + 5 + 0 = 9
Enter the 9 in the sum row of column #4
1 + 3 + 5 + 0 = 9
Enter the 9 in the sum row of column #4
| col # | 1 | 2 | 3 | 4 | 5 | 6 |
| carry | 1 | |||||
| + | 1 | 2 | 3 | 4 | 0 | |
| 5 | 6 | 7 | ||||
| 8 | 9 | 1 | 0 | 0 | 0 | |
| sum | 9 | 0 | 7 |
Column #3 (Tens place) Steps:
2 + 0 + 1 = 3
Enter the 3 in the sum row of column #3
2 + 0 + 1 = 3
Enter the 3 in the sum row of column #3
| col # | 1 | 2 | 3 | 4 | 5 | 6 |
| carry | 1 | |||||
| + | 1 | 2 | 3 | 4 | 0 | |
| 5 | 6 | 7 | ||||
| 8 | 9 | 1 | 0 | 0 | 0 | |
| sum | 3 | 9 | 0 | 7 |
Column #2 (Hundreds place) Steps:
1 + 0 + 9 = 10
Enter the 0 in the sum row of column #2
Carry the 1 to the top of column #1
1 + 0 + 9 = 10
Enter the 0 in the sum row of column #2
Carry the 1 to the top of column #1
| col # | 1 | 2 | 3 | 4 | 5 | 6 |
| carry | 1 | 1 | ||||
| + | 1 | 2 | 3 | 4 | 0 | |
| 5 | 6 | 7 | ||||
| 8 | 9 | 1 | 0 | 0 | 0 | |
| sum | 0 | 3 | 9 | 0 | 7 |
Column #1 (Thousands place) Steps:
1 + 0 + 0 + 8 = 9
Enter the 9 in the sum row of column #1
1 + 0 + 0 + 8 = 9
Enter the 9 in the sum row of column #1
| col # | 1 | 2 | 3 | 4 | 5 | 6 |
| carry | 1 | 1 | ||||
| + | 1 | 2 | 3 | 4 | 0 | |
| 5 | 6 | 7 | ||||
| 8 | 9 | 1 | 0 | 0 | 0 | |
| sum | 9 | 0 | 3 | 9 | 0 | 7 |
The result of adding 123.4, 5.67, and 8910 using long addition is 9039.07.
