yego.me
💡 Stop wasting time. Read Youtube instead of watch. Download Chrome Extension

Introduction to multiplication


2m read
·Nov 11, 2024

Our squirrel friend here likes to collect acorns because, really, that's how he is able to live. Let's say every day he collects exactly three acorns. So, what I'm curious about is how many acorns will he have after doing this for five days?

One way to think about it is every day he is able to collect a group of three acorns. You could view this as maybe what he's able to collect in day one. Then, in day two, he's able to collect a second group of three acorns. In day three, he's able to collect another group of three acorns. Every day is the equal number of acorns that he's collecting. On the fourth day, another three; on the fifth day, another three.

If you were curious how many total acorns he's collected, well, you could just count them up. Or you could think about, well, he's got five groups of three acorns, five equal groups of three acorns. So, you could say five groups of three acorns; three acorns. The total amount would be five.

We could view this as five threes. Now, five threes you could view this as five threes added together: three plus three plus three plus three plus three. If you wanted to calculate this, you could skip count by three. So this would be 3, 6, 9, 12, 15, because we add 3, we get to 6, we add another 3, we get to 9, we add another three, we get to 12, we add another three, we get to 15.

And so, this would be a way of recognizing that you have 15 acorns. But we're starting to touch on one of the most fundamental ideas in all of mathematics. In fact, we actually are applying it; we just haven't used the word. And that's we are multiplying. We are using multiplication.

All multiplication is, is this notion of multiple equal groups of something. So here, one way to express what we just did is we just—when we said five threes— that's the same thing as five. And I'm going to introduce a new symbol to you: five times three. So all of these things are equivalent.

You're already used to seeing equal groups and multiple equal groups. You're used to adding something multiple times, and you're used to skip counting. All of that is, in some way, shape, or form, you have been doing multiplication. So when someone says 5 times 3, you could view that as 5 groups of 3, or you could view that as five threes, or you could do that as three plus three plus three plus three, or you could view that as fifteen.

I'll leave you there. There's a lot of practice on Khan Academy to work through this and make sure you get the underlying idea. But, as you'll see, this is perhaps one of the most useful concepts that you might learn in your entire lives.

More Articles

View All
Definite integral of radical function | AP Calculus AB | Khan Academy
So we want to evaluate the definite integral from -1 to 8 of 12 * the cube root of x dx. Let’s see, this is going to be the same thing as the definite integral from -1 to 8 of 12 * the cube root is the same thing as saying x to the 1⁄3 power dx. And so n…
The Stock Market Is ABOUT TO BOTTOM
What’s up, Grandma’s guys? Here, so it’s official: the market makes absolutely no sense. Tesla beat earnings, and as a result, they drop. The US GDP topped expectations, and shortly after, the entire market falls. Even gold, which typically does well in …
TAOISM | The Art of Not Trying
Those who stand on tiptoes do not stand firmly. Those who rush ahead don’t get very far. Those who try to outshine others dim their own light. — Lao Tzu How can we improve when we stop trying to improve? Many people waste their efforts trying to better …
"Where Love Is Illegal": Chronicling LGBT Stories of Love and Discrimination (Part 3) | Nat Geo Live
Our activism is continuing to evolve. In the next phase of Where Love Is Illegal, we are enduring to leverage our storytelling skills so we can further amplify the voices of LGBTQI+ communities around the world. And we’re doing just that in Jamaica. Last …
Warren Buffett's Financial Advice to Students
Testing 1 million, 2 million, 3 million that’s working okay. I’d like to, uh, talk to you about your financial future and I hope those figures become applicable to all of you as we go along. At, uh, uh, and I’d like to start, uh, by posing a problem for …
Introduction to inference about slope in linear regression | AP Statistics | Khan Academy
In this video, we’re going to talk about regression lines. But it’s not going to be the first time we’re talking about regression lines. And so, if the idea of a regression is foreign to you, I encourage you to watch the introductory videos on it. Here, w…