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00:00Well, as we mentioned earlier, today we are going to learn about multiplication.
00:05You're going to learn how to multiply, and if that sounds really scary or if that sounds
00:09like a difficult thing, it's just because you don't know how to do it yet.
00:14Once you learn the game, once you learn the process, it's fun, it's awesome.
00:21You see, multiplying is like being a detective.
00:24You're cracking a code, which is so cool.
00:27You're solving mysteries, like legit mysteries.
00:30I'm in an office building right now, there's a cake behind me, for some reason I'm looking
00:35out right now at you guys and I see that you're like, whoa, we're going to multiply!
00:41And once you learn it, it's just a game, so buckle in for the fun and the learning.
00:48Let's say you have two bikes, and for some reason they look the exact same, and somebody
00:54wants to give you an air pump.
00:58They ask a simple question, how many tires do you have to take care of?
01:05To figure that out, we're going to use multiplication, we're going to play the game, it's going to
01:10be awesome!
01:12Okay, so here is how multiplication works.
01:18So we put the number that's in each group, and then we put this x, which means times,
01:25and then the number of groups.
01:26So that tells us how many times that number is going to show up, and then we add them
01:31all together, and you've got your answer!
01:34Isn't that cool?
01:37And just a side note, to work, there has to be the same number in each group.
01:45Now remember, we're trying to figure out how many tires you have to take care of if
01:49you have two bicycles.
01:53Alright now, we have the wheels under each bike, each bike has two wheels, one, two.
02:05So we write down a two, each bike has two wheels.
02:13Remember the first number we write down with multiplication is the number in each group.
02:21Then we write an x, this x means times, two times, it's the symbol of multiplication.
02:32Alright the second number we write are the number of groups, you can see them here.
02:37How many groups do we have of two?
02:41How many?
02:42Yeah, two!
02:45So it reads two times two.
02:51To figure this out, we are going to skip count by two.
02:56Two, four.
03:01That means two times two equals four.
03:06If you have two bikes, that means you have four wheels.
03:09Two, two times, is four.
03:16Remember this is how multiplication works.
03:20The number in each group times the number of groups equals your answer.
03:28Of course to work, there has to be the same number in each group.
03:35Alright let's take this to the next level.
03:37Let's say someone has four bikes.
03:42And here are their wheels.
03:47You know how to do this now.
03:48Each bike has two wheels, so the first number we write down is the number two.
03:53That's the number in each group.
03:59We're going to put the time symbol there and count the number of groups.
04:02One, two, three, four.
04:04So it's two times four.
04:09This is so much fun!
04:10This is multiplication!
04:16Now let's skip count to get the answer.
04:18Two, four, six, eight.
04:25Eight is our answer.
04:26There are eight wheels.
04:27Two times four equals eight.
04:31This is how multiplication works.
04:37We put the number in each group times the number of groups and we get our answer!
04:44You're getting the hang of it.
04:46Alright let's try this one.
04:51Let's say you buy three packs of trading cards.
04:56Let's say each pack had five cards in it.
04:59Huh, that's a pretty good amount.
05:01So three packs of five cards.
05:08How many cards did you get in total?
05:10That's a really great question.
05:13Sounds like we're going to need to multiply.
05:19So each group has five, so that's the first thing we write down, the number in each group.
05:24That's five.
05:26Take the multiplication sign, which is the X, which means times, five times.
05:36How many groups are there?
05:37One, two, three.
05:40So the second number is three.
05:43Five times three.
05:46What's five times three?
05:48We're going to skip count to find out.
05:51Five, ten, fifteen.
05:58Five times three equals fifteen.
06:01You have fifteen trading cards.
06:08Alright this is how it works.
06:11You take the number in each group times the number of groups and you get your answer.
06:20Now here are some multiplication tricks that are going to be really sneaky ways that you
06:25can figure out multiplication problems really, really quickly.
06:30Here's the trick.
06:31If you multiply any number by zero, you always get zero.
06:37Always you always get zero.
06:43Here's an example.
06:44Five times zero equals zero.
06:47When you have zero groups of five, that means you have zero.
06:50There are none.
06:52Whenever you multiply any number by zero, you always get zero.
06:56One hundred times zero equals zero.
07:04Even if zero is the first number in the equation, you still always get zero when you multiply
07:10by any number.
07:12For example, zero times eleven equals zero.
07:19And zero times one thousand equals zero.
07:23If you multiply any number by zero, you always get zero.
07:29Oh this has been so much fun.
07:31Here is the next trick.
07:37If you multiply any number by one, it stays the same.
07:42Look at these.
07:43Seven times one equals seven.
07:45One hundred times one equals one hundred.
07:48Thirty three times one equals thirty three.
07:55If you flip them, the answer stays the same.
07:58One times seven equals seven.
08:00One times one hundred equals one hundred.
08:02One times thirty three equals thirty three.
08:05Honestly, the order of the multiplied numbers does not change the answer.
08:14If you were to flip the number of groups and the number in each group, you would still
08:19get the same answer.
08:22Though we still recommend this way.
08:24So simple.
08:25The number in each group times the number of groups to get your answer.
08:34So the two tricks have been, if you multiply any number by zero, you always get zero.
08:44And if you multiply any number by one, it stays the same.
08:49The final multiplication trick is to use multiplication tables.
08:59They come in all shapes and sizes, but they are all helpful, especially as you're first
09:04learning how to multiply.
09:06Here are some examples of multiplication tables.
09:09There's a table for all of the numbers from one to ten.
09:17Some kids memorize tables like these so that they'll know right off the bat, in a moment,
09:24what an answer could be for certain multiplication problems.
09:29This is how multiplication works.
09:31The number in each group times the number of groups gives us our answer.