Write the problem on the board so students can see it clearly. Tell them to write the problem on a piece of paper. For example, use the equation 23 - 18 = x.
Give the students physical objects to represent the numbers and number places. For example, use a pretzel stick to represent tens. For the number 23, give each student two pretzel sticks.Use smaller pretzels, such as nuggets or minis for the ones place. For the number 23, give the students three nuggets.
Line up the objects on a flat surface.
Explain the concept of regrouping as trading in one object for the equivalent of the other. For example, a single pretzel stick is equal to 10 pretzel nuggets.
Show the students how to regroup by borrowing 10 from the tens place so that they can subtract 8 from 3. Have the students trade in a pretzel stick for 10 nuggets. Tell them to place the additional 10 nuggets next to the three nuggets.
Tell the students to take away eight nuggets from the 13 they have lined up on their desks. Make the demonstration more concrete by having them eat the eight pretzel pieces. Have them count the number of nuggets that remain and write the number on their paper, below or next to the equal sign.
Have the students take away one pretzel stick from the tens place to subtract the "1" in the tens place of 18. They can eat the pretzel stick to drive home the point. Ask them how many tens remain. The answer should be zero.
Ask the students the answer to 23 - 18. They should respond with 5. If they do not, ask them to look at how many pretzels remain on their desks.