Long Addition Calculator for Adding Multiple Whole Numbers and Decimals

Long Addition Calculator Sign

This sum of numbers calculator will add the entered whole numbers or decimals and display the columnar grid used for finding the sum.

Plus, the columnar grid includes buttons that can be clicked to display the steps for each column.

Note if you want to multiply or divide numbers, you can use the Long Multiplication Calculator or the Long Division Calculator.

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Long Addition Calculator

Calculate the sum of multiple whole numbers or decimals and see the step-by-step column method for adding numbers without a calculator.

Special Instructions

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Selected Data Record:

A Data Record is a set of calculator entries that are stored in your web browser's Local Storage. If a Data Record is currently selected in the "Data" tab, this line will list the name you gave to that data record. If no data record is selected, or you have no entries stored for this calculator, the line will display "None".

DataData recordData recordSelected data record: None
Numbers:Numbers:Numbers to add:Numbers to add:

Numbers to add:

Enter the positive numbers you would like to add, with each number separated by a comma or a line return. For example, you can enter the numbers like this:

123, 456, 789

Or like this:

123
456
789

Note that the numbers can contain decimal points, but neither the whole number or the decimal portion can exceed 9 digits.

Sum:Sum of #s:Sum of numbers:Sum of entered numbers:

Sum of entered numbers:

This is the calculated sum of the numbers you entered. Please check to make sure the sum in the interactive tutorial matches the sum in this row. If not, please expand and complete the Feedback form beneath the calculator to let me know.

If you would like to save the current entries to the secure online database, tap or click on the Data tab, select "New Data Record", give the data record a name, then tap or click the Save button. To save changes to previously saved entries, simply tap the Save button. Please select and "Clear" any data records you no longer need.

Help and Tools

Learn

How to Add Numbers Without a Calculator

Steps to Adding Numbers Without a Calculator

  1. Stack the numbers on top of each other with like places and decimal points vertically aligned.
  2. Start in the right-most column and work from right to left.
  3. Add the column's numbers together, including any carryover, to get the column sum.
  4. If the column sum is less than 10, place the sum beneath the column.
  5. 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.
  6. 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 #123456
carry    
+ 12340
   567
891000
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
col #123456
carry    
+ 12340
   567
891000
sum7
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
col #123456
carry  1  
+ 12340
   567
891000
sum07
Column #4 (Ones place) Steps:
1 + 3 + 5 + 0 = 9
Enter the 9 in the sum row of column #4
col #123456
carry  1  
+ 12340
   567
891000
sum907
Column #3 (Tens place) Steps:
2 + 0 + 1 = 3
Enter the 3 in the sum row of column #3
col #123456
carry  1  
+ 12340
   567
891000
sum3907
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
col #123456
carry1  1  
+ 12340
   567
891000
sum03907
Column #1 (Thousands place) Steps:
1 + 0 + 0 + 8 = 9
Enter the 9 in the sum row of column #1
col #123456
carry1  1  
+ 12340
   567
891000
sum903907

The result of adding 123.4, 5.67, and 8910 using long addition is 9039.07.

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Adjust Calculator Width:

Move the slider to left and right to adjust the calculator width. Note that the Help and Tools panel will be hidden when the calculator is too wide to fit both on the screen. Moving the slider to the left will bring the instructions and tools panel back into view.

Also note that some calculators will reformat to accommodate the screen size as you make the calculator wider or narrower. If the calculator is narrow, columns of entry rows will be converted to a vertical entry form, whereas a wider calculator will display columns of entry rows, and the entry fields will be smaller in size ... since they will not need to be "thumb friendly".

Show/Hide Popup Keypads:

Select Show or Hide to show or hide the popup keypad icons located next to numeric entry fields. These are generally only needed for mobile devices that don't have decimal points in their numeric keypads. So if you are on a desktop, you may find the calculator to be more user-friendly and less cluttered without them.

Stick/Unstick Tools:

Select Stick or Unstick to stick or unstick the help and tools panel. Selecting "Stick" will keep the panel in view while scrolling the calculator vertically. If you find that annoying, select "Unstick" to keep the panel in a stationary position.

If the tools panel becomes "Unstuck" on its own, try clicking "Unstick" and then "Stick" to re-stick the panel.