Addition in Columns
We can do addition by writing one number below the other
and then add one column at a time, like this:
(Practice on this Simple Column Addition Worksheets)
And it works for bigger numbers, too:
But sometimes twodigit numbers can get in the way like this:
THIS is how it should be done:
Did you see how we split the 12 into 1 Ten and 2 Units? We then sent the 1 Ten to the top of the Tens column, so we will remember to add it when we do the Tens. 

And there is a nice clear space for the Tens answer below. 
Here's another example (done a little faster):
Now practice on this Column Addition (with Carrying) Worksheets
Above or Below?Your teacher may want you to put the "1" below like in this example. Above or below does not really matter, we just need a good place to put the "1" so we don't forget it! 
What About Bigger Numbers?
The same method works with numbers in the hundreds, thousands and so on.
Like this: