Here we go with subtraction! When I was in Elementary School there was something about subtraction that I didn't like... Maybe this was because we became so comfortable with addition we didn't want to try something different. In this class we have gone over several different methods to do subtraction.
Examples
Examples
The definition of subtraction says that we can compute the difference 17-5 by determining the missing addend.
Missing addend: finding the number that must be added to 5 to give 17.
Cashiers often use this approach when making change. It is simpler to pay back the change by counting up rather than down. For example, Jimmy bought a candy bar for 85 cents with a one dollar bill. The cashier then counts 90 by adding a nickel. Then a dime reaches $1.
I think kids would like to learn subtraction this way, because it's just like addition. Once or twice a week I take Madaline to preschool and it never fails, she always finds either a dime or a quarter in the back seat. She gets so excited and says, "I'm putting this in my piggy bank!" Kids love money, even if it is just a coin or two. I think learning addition and subtraction with money would keep their interest and make learning fun.
Taking away concept
Suppose that Emily has 4 blocks and gives away 2. How many blocks will she have left?
1. Start with the 4 blocks and then take away 2.
2. The take away concept shows that 4-2=2.
Center for Theoretical and Computational Materials Science, NIST
The take away concept should be easy for kids to understand, especially for ones who don't like sharing! It is an easy method to explain and understand.
Comparison Concept
Center for Theoretical and Computational Materials Science, NIST
The take away concept should be easy for kids to understand, especially for ones who don't like sharing! It is an easy method to explain and understand.
Comparison Concept
The comparison concept is a nice visual way to see subtraction. However, it is not very useful when using large numbers.
Missing Addend Concept
Suppose that you have 6 stamps and you need to mail 10 letters. How many more stamps are needed? In this case we can count up from 6 to 10 to find the missing addend.
++++
+ = 10
The missing addend concept is the most popular method for subtraction. When I was in Elementary School I don't remember being taught this. It makes sense on why it is so comfortable to use, because it is addition.
Video by: Harry Kindgergarten
I think you do a great job with the break down of the subtraction process. If you were teaching this for the first time with props and examples, the viewer would have a well understanding of what to precieve. Good job!
ReplyDeleteShayna W-
I like this breakdown of the subtraction process.
ReplyDeleteChris Pape
This is a good way to teach you kids to count the change, when they buy things at the store. lisa
ReplyDeleteI love the way you presentated examples and broke them down it's very helpful and I know when giving these to examples to elementary students they would be able to understand the steps needed to complete these problems.
ReplyDeleteI'm excited that we are learning different ways to explain subtraction because i was only taught one way when i was younger. I also had a hard time understanding the concept. Leaning more than one way to explain a difficult concept will help me become a great teacher.
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