Learn about Addition of Whole Numbers Let's learn about addition of whole numbers. Let's do the first problem first which is to evaluate and check; 256 add it to 664. 256 added to 664, by the way these two are called addends and the sum of them is called the sum. So in order to do this, what we do is rewrite the numbers down, layered on top of each other. Then, we start adding from the right to the left. So, what we do is add the digits in each of the columns starting from the right most digits; 6 + 4 gives us 10. We’re only allowed to write one digit down and we have to carry over this other digit of 10 in this case to the left side. So this column becomes 1 + 5 + 6 which is 6 + 6 is 12. I’ll write two down, carry over one, 1 + 2 + 6 is nine. So the answer is 920. Now I can check that because both of these numbers are being added so there is a commutative property which says 256 + 664 is the same as 664 + 256. I can reverse that. So in this case, let's check what happens if I add 664 with 256. We’ll do exactly the same thing; 4 + 6 becomes 10, 1 + 6 + 5 is 7 + 5 = 12, 6 + 2 + 1 is 9. I get the same answer which is correct. So the final answer that I'm looking for is 920. Now let's look at the second problem which says that Martha went to a bookstore to buy some books and files. The price of the book was $50.00. The price of the file was $43.00. What's the total amount of money she’s going to pay? Well, all we have to do is look at the price of the book, it was $50.00 and the price of the file was $43.00. So what she’s going to pay is $50.00 and $43.00 added. Let's add these; 0 + 3 is 3, 5 + 4 = 9. So what she’s going to pay is $93.00. Recapping what we've learned. If we’re adding two numbers, we can add the columns and just remember to carry them over if the end result is greater than nine or two digits. We put the first digit here and the second digit here. So this gives us an addition of 920.Similarly here, we get the value of 93.