The number 25 has 2 tens and 5 ones. Now let's write this out as a column addition to work out the answer. You can use place value headings to help. Start with the column furthest to the right.

With practice, breaking numbers down into hundreds, tens and ones can make addition easier. Using place value counters can help you visualise addition by showing how numbers combine in each place ...

Use “tens” and “ones” to explain the meaning of a two ... the place values and explain the thinking involved. Understand addition as “putting together” and “adding to.” ...