Video:How to Do 2-Digit Addition Without Grouping

Transcript:How to Do 2-Digit Addition Without Grouping

Hi, my name is Bassem Saad, I'm an associate math instructor and a Ph.D. candidate, and I'm here today for About.com to show you how to do two-digit addition without regrouping. As a reminder, a digit is any number from zero to nine and when doing two-digit addition, we work from right to left.

Add the First Digits to Do 2-Digit Addition Without Grouping

So, the number 35 is actually two digits: the first digit is five and the second digit is 3. So say we want to add 35 to 12. Well, there's just two easy steps: The first thing you want to do is add the first digit in the first number to the first digit in the second number. In this example, the first digit for the first number is five. The first digit for the second number is two. So we just add five plus two, which equals seven. We record that number immediately under the first digit in the second number. So seven goes just below the five and the two.

Add the Second Digits to Do 2-Digit Addition Without Grouping

Now we're ready for the second step. Add the second digit for the first number to the second digit of the second number. The second digit of the first number is three, the second digit of the second number is one, so that's three plus one equals four. Well, we just record that four immediately underneath the second digit in the second number. And so now we know that 35 plus 12 equals 47.

Another Example of 2-Digit Addition Without Grouping

Let's take a look at one more example. Say we want to add 59 to 30. Well, our first step again is to add the first digits, so that's nine plus zero, and nine plus zero is just nine and we record that immediately underneath the zero. Second step: we add the next digits, so five plus three, that's just eight. So the answer is 89. So that was two-digit addition without regrouping.

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