Adding two numbers

First add the numbers in the ones column.

Then add the numbers in the tens column.

Finally add the numbers in the hundreds column.

If the answer to any is a two digit number, put the second digit in the box and the first digit under the next column as shown below. (Don't forget to add it on when you add your next column.

Subtracting two numbers

Start with the ones column. If the number on the top is smaller than the one below you need to go next door for a ten.

Borrow a ten and remember to change that number and put the 10 with the number already in the ones column.