Second Grade Math Lesson Plans and Sample Exercises

Second Grade Math Lesson and Exercises

Lesson Plan

Objective

Students will 'decompose' the numbers in an equation by breaking the numbers down into factors, especially tens and ones. For example, students can break down the numbers in the equation 12 - 4 like so: 12 - 4 = 12 - 2 - 2 = 10 - 2 = 8. In this way, students can begin learning about subtraction facts up to ten.

Procedure

1. Review addition up to nine.
   On the board, draw two small circles and color one of them in. Say something like, 'Remember that 1 + 1 = 2.' Write the equation on the board and point to the circles. Then add, 'Well, 2 - 1 = 1,' again pointing to the circles and writing the equation.
   
   Add another circle and use the same procedure to review 1 + 2 = 3, 2 + 1 = 3, 3 - 1 = 2 and 3 - 2 = 1. Continue through the nines, having the children give you the equations to write each time.
   
   
2. Review place value for units and tens.
   Divide children into groups up to ten; give each group 99 Popsicle sticks, nine rubber bands and two plastic tubs labeled 'Ones' and 'Tens.' Going around the group, have each student put one Popsicle stick into the tub labeled 'Ones.' Count out loud as each student does this and write a column of numbers on the board while you count.
   
   When you get to 'ten,' put a rubber band around the ten sticks together and transfer the bundle into the 'Tens' tub. You can repeat this to 99.
   
   
3. Decompose to subtract.
   Hold up a bundle of ten sticks and two more individual sticks. Say, 'We have 12 sticks. How can we subtract four sticks?' They'll likely tell you to subtract the two individual sticks; you can guide them to see that you must subtract two more sticks from the bundle of ten.
   
   Write each step on the board as you do this: 12 - 4 = ?, 12 - 2 = 10, 10 - 2 = 8. Then combine the steps to show that 12 - 4 = 12 - 2 - 2 = 10 - 2 = 8. Then say, 'Even though you didn't know that 12 - 4 = 8, you could figure it out in your head by going through the steps we just followed.
   
   
4. Repeat with more problems.

More Activities

Give each child one die and a picture of a centipede with 20 legs or less. The students will then roll the die and cross off the number of legs that the die shows. For each roll, the student will write the equation for what he did. Do this until all of the legs are crossed off. His equations might be 20 - 1 =19, 19 - 5 = 14, 14 - 8 = 6, etc.

Act out a story. Read a book such as The Doorbell Rang by Pat Hutchins and act out the addition and subtraction as you come to it.

Use flash cards. Tape a set of flash cards to the board at the front of the class, displaying all of the subtraction combinations up to ten. Ask questions like, 'Which equation equals two?' Remove a card once it has been used.