How to Teach Two Digit Subtraction for First Grade Math

Two-digit subtraction is the act of taking away or subtracting a double digit number from another double digit number. For example, the problem "32-12= ??" will be used to illustrate the process of two-digit subtraction.

Things You'll Need

• Pen
• Paper

Instructions

1. Sit your child down in a comfortable environment and have a pen and paper ready. Then write a simple 2-digit subtraction problem for the children--the simpler the better. For example, 32-12= ?

2. Write the equation in the following format so it is easy for the child to visualize the equation: 32- 12------- ? ?

3. Ask the child to read the equation from the right to the left. In two-digit subtraction, subtraction is first applied to the last number of the two digit number, or from the column furthest to the right. In this example, you should ask, " What does 2 -2 equal?" They should know that it equals 0, and when they have given you a correct answer, write the number 0 at the bottom of the right column in the following way: 32- 12-------- ?0

4. Then ask the child, what 3-1 equals and they should answer with "2." Then, write down the complete answer to the equation: 32- 12------ 20Remember that this is because you want to start using the subtraction process from the column furthest to the right and work your way left. In the example, by subtracting the right column and then the left column, we've come up with the answer: 32-12=20.