We have a good selection of maths worksheets covering the standard written method of addition. We begin this with using just 2-digit numbers, although it should be pointed out that usually 2-digit addition should be tackled ‘in your head’.
The standard method is to add the units first, put the units in the answer, and ‘carry’ the ten into the tens column. Then add the tens. detailed examples and plenty of preactice can be found in our Four Rules section under written addition.