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

Estimating with multiplication


2m read
·Nov 10, 2024

In this video, we're going to get a little bit of practice estimating with multiplication. So over here, it says question mark is, and you have the squiggly equal sign. You could view that squiggly equal sign as being, "What is this roughly equal to?" It doesn't have to be exactly right.

So what is roughly equal to 58 times 6? Which of these choices would you pick? Pause the video and see if you can answer that.

So, once again, we don't have to get this exactly; we just need to estimate what 58 times 6 is. The way that I would tackle it is, "Hey, can I rewrite 58 as a number that’s easy to multiply by 6, or easy to multiply in general?" The easiest thing I can think of is 58 is awfully close to 60.

If you say that that is close to 60, if we're just estimating it, well, what would 60 times 6 be? Well, 60 times 6 is the same thing as—actually, let me just write it this way—you could do 60 times 6 as 6 times 10 times 6, which you could also view as 6 times 6 times 10.

And what's 6 times 6? That's 36. Then 36 times 10 is 360. So I would go with that choice right over there. Notice these other choices aren't even close to that, so we feel pretty good about our estimation.

Let's do another example. So here's where I asked, "What's three times 2890? What's that roughly equal to?" How would you estimate this? Pause the video and see if you can figure that out.

All right, so 2890 is not an easy thing to maybe multiply in our heads, but I can say, "Hey, that’s kind of close to three thousand." So I'm going to say that this is going to be approximately equal to—or roughly equal to—three times three thousand.

Now what's 3 times 3? That's 9, so 3 times 3,000? Well, it's going to be 9 thousands, and so it would be this choice right over there. Here, what I just did was a little bit confusing. You could view 3 times 3,000 as three times three times a thousand. This part right over there is three thousand.

Three times three is the 9, and you have nine thousands, nine thousand. Let’s do one more example. This is going to involve fairly large numbers. So what is, if you had to estimate 5,111 times 9, which of these would you pick? Pause the video and answer that.

All right, so I would view this—this is roughly—I would estimate it as five thousand times 9. So five thousand times 9, that’s the same thing as five times a thousand times 9, which is the same thing as five times 9 times a thousand.

Five times 9 is forty-five, so it's going to be forty-five thousands or forty-five thousand, which is this choice right over there.

More Articles

View All
Behind the Scenes With Director Everardo Gout | MARS
Presented by Acura. Precision crafted performance. Retro Rockets are about to fire in 1, 2, 3! Hello, my name is Ardo Good, and I’m the director of the miniseries. I was drawn to this project mainly because of two things. One is that I always try to look…
The 5 Step Process for Getting What You Want From Life
Like I say, you can have practically anything you want in life, but you can’t have everything you want in life. So that means you have to prioritize what are the things you’re going after. That has to do with the earlier part of, you know, know what you’r…
Why more people started flying in private jets
What do you think COVID did for the private aviation industry? Because I’ll be honest, when that whole thing was going on, that was kind of my first introduction to… staring. The charter travel got very crazy. Even though prices were quite crazy at that t…
Khan Academy Districts Overview
Foreign [Music] The benefit that Khan Academy brings to our school district is being able to provide a platform that provides individualized practice study skill. The ability for students to increase their knowledge proficiency. The support that Khan Aca…
The Ponzi Factor | Stocks are NOT Ownership Instruments
The reason why finance professionals do not see the stock market as a Ponzi scheme is because they believe the credibility for an idea rests on repetition, tradition, and people who recite it rather than proof, logic, or facts. The first fallacy, which I…
Comparing P value to significance level for test involving difference of proportions | Khan Academy
A veterinarian is studying a certain disease that seems to be affecting male cats more than female cats. They obtain a random sample of records from 500 cats. They find 24 of the 259 male cats have the disease, while 14 of 241 female cats have the disease…