Provide the students with base-10 manipulative blocks. Make sure each child has at least five blocks that represent the "tens" and about 30 blocks that represent the "ones."
Instruct students to divide a piece of paper in half. Label the left side as "tens" and the right side as "ones." You could also provide the students with this paper already prepared.
Determine a math problem to begin with such as "14 + 28" and prepare students to set up the problem on their paper using the manipulatives.
Explain that to represent "14," they will need to place one "tens" block into the left column and 4 "ones" blocks into the right column. Underneath those blocks, guide the children to place two "tens" in the left column and eight "ones" into the right to represent "28."
Support the students to count all of the blocks in the "ones" column. Have them take 10 "ones" away, exchange them for a "tens" block, and place it in the "tens" column.
Instruct students to count how many "tens" blocks are in the left column and write the number "4" in the same column. Then count the blocks in the right column and write the number "2." Children will see that the answer is "42."
Write a subtraction problem on a board that all students can see it, such as "83 -- 26." Stack the numbers vertically so "83" is on top and "26" is on the bottom.
Draw a line to separate the "tens" and "ones" columns through the two numbers that are stacked.
Explain to the children that you cannot subtract "6" from "3," so you must regroup from the "tens" column.
Remind students that the "8" in the "tens" column actually represents "80." So they will take "10" away from "80," cross out the "8" and write "7" above it.
Add the "10" that was taken away from the left hand column to the "3" in the "ones" column. It will become "13." The children can now subtract each column and write the answer at the bottom of the problem. Subtract "6" from "13" the "ones" column to equal "7." Subtract "2" from "7" in the "tens" column to equal "5." The answer computes to "57."