Chapter 2 Subtraction is Where It Is At!!
Chapter 2 Subtraction is Where It Is At!!

 

 

  Chapter 2- 

 

We cannot have addition without subtraction so jump on the subtraction bus and here we go!!

 

 

 

Subtraction is more than "take away"!

Subtracting is used to show separating situations and can be shown in a subtraction sentence that uses a minus " - " sign and an equal = sign to show the answer. The big idea that we focus on here is that the biggest number is always in the front of a subtraction sentence and the smallest number is the answer. There are three kinds of subtraction sentences that we focus on here. They are-

 

 

1.       Amount Left Unknown-

Tracy has 7 old baseball cards. She gives 4 of them to Jeff. How many does she have left?

7 - 4 = ?

 

2.       Amount Taken Away Unknown-

Tracy had 7 old baseball cards. She gave some to Jeff and had 3 left. How many did she give to Jeff?

7 - ? = 3

 

3.     Initial Amount Unknown-

Tracy had some old baseball cards. After she gave 4 away to Jeff, she had 3 left. How many did she have to start with?

? - 4 = 3

 

Now that we have all of the technical stuff out of the way here are the subtraction strategies that we will be using to help us figure this all out. Some might look familiar from a chapter ago...

1. Draw pictures of the groups. 

This is where you can see the budding artists start to come out. While we love ourselves some good artwork, make sure that the math is the focus. We make quick pictures in class and save the masterpieces for our other projects. Draw one group of the sentence and then cross out the next number and see how many are left. (imagine that the far ones are crossed off)


5  - 2 =


               
‚Äč                            

2. Use objects. Grab anything small around the house and put them in groups. From cars to dolls to raisins to chocolate chips, you can use anything to represent the subtraction in math stories!! If you use food you can always eat it!!

 

3. What do you do with a zero? Just like adding if you see a - 0 just keep on going and pretend like nothing is there. That is subtracting NONE.

If you see 7-7 then you want to take ALL.

 

 

Activities for Chapter 2 Concepts

 

 

2.      Activity 2- Separating Stories

 

Materials needed: counters

 

Procedure:

1.      Pose this story to the child:

"I saw 9 kittens in a basket. 3 kittens were sleeping. How many kittens were not sleeping?"

2.      Count out 9 counters and display them. Have the child separate 3 cubes from the group. Ask "How many counters are left?"

3.      Repeat with other stories and discuss how to separate or "take away" the counters that are not needed.

4.      Pose another story and have the child draw the picture by drawing the amount that is in the beginning and then crossing out the ones that are taken away.

5.      When eating you can pose stories and then have the child actually eat some and then say how many are left.