Addition: Whole Numbers
Addition , written using the symbol , is the mathematical operation that represents the total number of objects together in a collection.
For simple addition problems, you can count dots to find the answer.
There are blue dots and red dots. There are dots altogether.
To add numbers with more than one digit, you can visualize base ten blocks.
is equal to , so it can be represented by ONE block, ONE ten block, and FIVE unit blocks.
is equal to , so it can be represented by THREE ten blocks and SEVEN unit blocks.
To add, draw all the blocks together.
Altogether we have unit blocks, so we can trade them up for ONE ten block and TWO unit blocks.
Now we have or .
When you add by writing numbers vertically, and adding up the columns, you use "carrying," which is the same as the idea of trading up for the next-largest block.
First add the ones column. , so write down the and carry the one.
Next add the tens column. .
Next add the hundreds column. . Write down the and carry the .
Next add the thousands column. .