Oh hi everybody! Today I am going to talk to you about numbers,
and adding and subtracting numbers, and maybe even donuts. Ho, I really like donuts.
So, we all know that numbers can be joined together to make bigger
numbers. We call this adding. ADDING! And we also know that we can take away numbers
from bigger numbers to make smaller numbers. We call this subtracting. SUBTRACTING!
Let us use an example. We need a volunteer, how about… sloth. I said sloth!
OK. Here is a sloth. And we see that sloth has two donuts. One
two. What happens if we add one-two-three more donuts? Yes that’s right, sloth gets happier!
But also - mathematically - If we add two and three together we get five. Five donuts!
Now what happens if we subtract one-two-three-four donuts from sloth?
Yes that’s right, sloth gets sadder. But also - mathematically - if we have
five and we subtract four, we only have one left. One donut!
Wow, you did such a good job adding and subtracting it’s now… playtime! OK that’s enough!
So, we can add and subtract with donuts,
but did you know that we can also add and subtract with writing? No it’s true!
We can do it by writing the numbers - or numerals - and also by writing with signs.
This is a plus sign. PLUS SIGN! This is a minus sign. MINUS SIGN!
And this is an equals sign. EQUALS SIGN! And this is a monkey-riding-a-unicycle sign,
but we never use that one in math. Please go away monkey-riding-a-unicycle sign! OK great.
So, let’s add and subtract the same number of donuts with sloth, but this time,
also write the numbers and the signs. Ready? Of course you are. Sloth… sloth? Finally.
First the adding. Two donuts plus three donuts equals five donuts. Two plus three equals five.
Two. Plus sign. Three. Equals sign. Five. Happy sloth.
Now subtracting. Five donuts minus four donuts equals one donut. Five minus four equals one.
Five.Minus sign. Four. Equals sign. One. Sad sloth.
OK, let’s do another one, but with some different numbers, and different donuts. Ohhh, purple.
So, let’s see, we have one-two-three-four donuts and we add one-two-three-four-five
donuts, so we have - anybody know - that’s right, nine donuts!
Four plus five equals nine. Four. Plus sign. Five. Equals sign. Nine. Super happy sloth.
So I have a question. What do you think happens if we switch the four and the five
like this? Now how many donuts do we have? That’s right, the same number of donuts!
Nine donuts! So, four plus five equals nine, and five plus four also equals nine.
Four plus five equals nine, and five plus four equals nine! Everybody!
Four plus five equals nine, and five plus four equals nine! Happy sloth!
Four plus five equals nine, and five plus four equals nine! OK that's enough!
Hey wanna know something? Of course you do! The plus sign and the minus sign are kind of
like opposites! You know, opposites. Just like happy and sad, big and small,
and daytime and nighttime. Opposites! OPPOSITES! And we can use the plus and minus sign in opposite
ways with the same numbers to check if our math is correct. No really, Watch!
If five plus four is equal to nine, then nine minus four is equal to five.
Same numbers, different order, and different signs, but both are correct!
Five plus four equals nine, correct! Nine minus four equals five, correct!
Five plus four equals nine, correct! Nine minus four equals five, correct! OK that’s enough!
OK, let’s do one last example of adding, but with some different numbers, and different donuts.
Ohhh, sprinkles. Wow!
So, this one may be a little tricky. We have one-two-three donuts
and we add uh, no more donuts, so now we have... anybody know? That’s right, three donuts!
Do you know what is the number we use when we don’t have anything? That’s right, zero! ZERO! Ya!
So that means three plus zero equals three. And what if we had four donuts and we added zero?
That’s right, four plus zero equals four. And so even if you had a really really really high number of donuts,
like seventeen, and added zero, you would still have seventeen donuts! Yay!
Wow, you did such a good job adding zero, it is now… playtime! OK that’s enough.
That is all the time we have today for adding and subtracting. Don’t forget to subscribe to
our channel for more laughing and learning from Scratch Garden. And did you know that we have a
lot of videos with sloth? No really! I think you should add those sloth videos to your playlist. OK bye for now!