Write two columns on a board. On the bottom of the right-hand column, write "ones" and on the bottom of the left-hand column, write "tens."
Write a two-digit number on the board. Write the number that represents the ones in the ones column and the number that represents the tens in the tens column. For instance, for the number 15, write the number 5 in the "ones" column and the number 1 in the "tens" column.
Discuss with students what each number represents, reviewing place value. State different two-digit numbers and ask students into which column each of the digits in the numbers you have stated should go.
Draw a line down the center of a sheet of paper. On the bottom of the right-hand side of the paper, write "ones" and on the bottom of the left-hand side of the paper, write "tens." Make a sheet for each student.
Write a simple two-digit number on the sheet of paper. Place the number that represents the ones in the "ones" column and the number that represents the tens in the "tens" column. Write another simple two-digit number below the first two-digit number. Use two numbers that will not require regrouping, as this is only an introduction to two-digit addition.
Explain to students that they are going to add the numbers together. Explain that when they are adding two-digit numbers together, they must first add the numbers in the "ones" column and then the numbers in the "tens" column. Encourage students to solve the given problem and then provide them with more practice problems.