Comparing with multiplication
About this video
This video shows how to turn a sentence like '36 is three times as large as 12' into a multiplication equation. It also compares two numbers both ways: with addition (how much more) and with multiplication (how many times as large). It shows that on a computer you type * (Shift + 8) for multiplication.
You'll be able to
- write a 'times as large as' comparison as a multiplication equation.
- find how many times as large one number is than another.
- tell the difference between comparing with addition and comparing with multiplication.
Key words
- times as large as
- A way to compare two numbers by saying how many copies of the smaller number make the larger one.
- multiplication equation
- A number sentence with an equals sign that uses multiplication, like 36 = 3 * 12.
- asterisk (*)
- The star symbol used on computers to mean 'times'; you type it with Shift and 8.
Transcript
The number 36 is three times as large as 12. Write this comparison as a multiplication equation. So they're saying that the number 36, we'll type 36, is equal to 3 times 12. And I will use this little star thing. Let's see, if I were to put an x there, would that have worked as well?
No, they would have viewed that as 3x. So to get this little star thing, which is normally when you're typing on a computer how you show multiplication, to get that you have to press Shift and the number 8. And it also sometimes shows up on a numeric keypad. But by doing that, I was able to show multiplication.
So this could be read as 36 is equal to 3 times 12, or 36 is 3 times as large as 12. Let's check our answer. Got it right. Let's do a couple more of these. We can compare the numbers 4 and 20 using addition by saying that 20 is 16 more than 4. Fair enough. That's right.
We could also compare 4 and 20 using multiplication. Fill in the blank correctly to compare the numbers 4 and 20 using multiplication. So they're saying 20 is blank times as large as four. Well, we know that 4 times 5 is 20, or that 5 times 4 is 20. So 20 is 5 times as large as 4.
If I do 4 five times, I'll get to 20. So let me check my answer. There you go. Let's do one more. The number 6 is three times as large as 2. Write this comparison as a multiplication equation. So once again, we could write that 6 is equal to 2, and then I press Shift and the number 8 to get that times symbol, that little asterisk snowflake-looking thing.
2 times 3. So I could write it like that, or I could write 2 times 3 is equal to 6. Either of those would be completely valid things to say. So here I'm saying 6 is-- well, actually, I'd like to say it this way. I'd like to say three times as large as 2. I think that's a little bit more fun.
So this is exactly 6 is 3 times as large as 2. And we're done.
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