Hello guys, today we are playing with some

toys from my bathtub. We are going to learn about a few things today

that are really cool in addition and subtraction. We will use some of my toys to help us. Let’s take a look. Here are some ducks. We have 3 blue ducks and 7 yellow ducks. Can you tell me how many ducks we have in

all? We have 10 ducks all together. When you add 3 and 7 you get 10 ducks in all. Now here is something really cool. The ducks just moved position. Is the answer still the same? Yes, the answer is still 10, the same as before. In addition we have what we call the commutative

property. This seems like something difficult to understand

but it is not. All it means is that when we are adding numbers

together they can be switched around as much as you want and the answer will still be the

same. This only works for addition so remember that. Here is a math problem where we can use what

we just learned. It says if 8 plus 2 equals 10, then blank

plus 8 equals 10. We need to fill in the blank with the missing

number. We know that 8 plus 2 equals 10. We just learned that in addition we can switch

the 8 and 2 around and still get the same answer of 10. So to fill in the missing number what do you

think it will be? The missing number is 2. The numbers 8 and 2 were just switched. With the 2 in the blank we get 2 plus 8 equals

10 and that is true. Great job kids. Here is another math problem but this time

it is subtraction. The problem says “ If 9 subtract 4 equals

5, then 9 subtract 5 equals blank”. We need to fill in the blank. The first thing we should know is that subtraction

is not the same as addition. In addition we can switch the numbers around

but not with subtraction. But addition and subtraction are similar in

some ways. Let me show you what I mean. Here is a math mountain. If you are not familiar with a math mountain

that is just fine. At the top we have the total. At the bottom we have what we call partners

or addends. The total is 9 and the partners are 4 and

5. We can use both subtraction and addition with

this math mountain. If we add the 4 and 5 together we get the

total of 9. We can also subtract. Just like the first part of the problem below,

9 subtract 4 equals 5. Let’s solve the part of the problem we don’t

know. 9 subtract 5 equals what? You probably figured it out but let’s use

addition to find the answer. We will start at the partner we know which

is 5. Let’s count up from 5 until we get to the

total. Starting from 5 we count 6….7…….8……9

We counted 4 numbers so the other partner is 4 Amazing job. I’m sure you can now see that subtraction

and addition are related. I want to show you one last addition skill. The problem says 2 plus 6 plus 4 equals 12

is the same as 10 plus blank equals 12. When we are doing addition with more than

two numbers like this it is helpful to make groups of doubles or tens. In this example we can combine the 6 and the

4 together to make 10. Adding with ten is much easier than trying

to add 2 plus 6 plus 4. Many of you already know partners of 10 like

6 and 4, 5 and 5, 3 and 7, and so on. Now we just have to add 2 plus 10 which is

12. It saves us time to combine numbers that make

10 and then add the other numbers. So the blank in this problem should be filled

with what number? The answer is 2. Ten plus 2 equals 12. Great job again. That was a long lesson but it will help you

as you add and subtract. Thanks for coming, we will see you next time.

## Comments

Author

How important is it that my kids memorize these terms?

Author

Great vid and animation.

Author

Keep it up

Author

This is awsome

Author

Wow

Author

This is great thanks you for the awesome video you rock! Best Chanel ever!!

Author

How old are you

Author

Very good

Author

0-0 equals 0 if you swap them it still equals the same π

Author

The identity property is when you add zero plusβs something is that same number

Author

These are just a good job for my school math

Author

10

Author

WHAT

Author

2+8=10 8+2=10

Author

π€π€π€π€π€π€π€π€π€π€π€π€π€π€π€π€π€π€π€π±π€£πππ€£ππ€£ππ€£ππ€£ππ€£ππππ€£π€£ funny

Author

The add move property or the add switch property is more memorable, less needlessly and harmfully nerdy.

Author

912=900===yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyykkkkkkkkkkkkkkkkkkkkkkkk99999999999o99999999999tyyc.d[kzfgmv.gkcRwe]aw

;DS';[RDF,TGJHMH

DR<EOSFLKLDJGH7THR8KSUDOIFKC9UIOapzgxsdvfydgfcudxZIOKLPnbrhjtmr9egiuy,094t-w0re-.0tiy9rkoerpwlokglp;sa-s-wsthfjduak

Author

=======0yui

Author

π¦