This video teaches the correct order of operations for solving mathematical expressions, specifically demonstrating that -3² equals -9 (not +9) because the exponentiation occurs before the negation, and then shows how to solve 21 ÷ 9 using long division to get 2.333... (a recurring decimal) or 2 3/9 as a mixed fraction.
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5 out of 100 students got this right! 😳 Are you among the 5?Added:
I am sure a lot of people cannot solve this particular question here without a calculator. Now, we have -3 squared + 33 -3 / 3 squared, okay? Now, for us to solve this, what most people did was to write this -3 squared as -3 * -3 and they got positive 9, but this is wrong, okay? Now, to write this expression, the numerator here will be -3 squared, okay? We'll put this in parentheses and bring out the minus outside, okay? And write this + 33 -3, okay? Now, we're going to divide everything by 3 squared, okay? So, from here, 9 squared is 9, so we are going to have -9 + 33 -3 / 3 squared, okay? So, from here, let's continue over here.
So, we are going to have -9 + 33 will give us positive 24. So, we have 24 -3 / 3 squared, okay? So, in our next step, 24 -3 will give us 21 / 3 squared, okay? So, this will be equal to 21 / 3 squared is 9. Now, we have this as an improper fraction and I want us to use long division to solve this, okay? We're going to be using long division to solve this. Remember that we have We got our answer as 21 / 9, okay?
And this will be equal to the Now, 21 is the dividend, okay? We're going to draw this line and 9 is the divisor. While the result we are going to get is called the quotient, okay? Now, from here, there are four steps that are involved when you want to solve a question using long division, okay? So, let's write those steps, okay? Let's write the steps here.
Now, the first step is division.
Division.
Okay, the second step is multiplication.
Multipli- -cation.
Now, the third step is subtraction.
The fourth step is to bring down, okay?
Bring down.
Now, all these steps are very, very important, okay? Now, before we continue solving this, we are going to write the multiplication of this number nine to a certain number, okay? So, we are going to have nine times one will give us nine. Nine times two will give us 18.
Nine times three will give us 27. Nine times four will give us um 36, okay?
Now, we can stop here. You can continue, but I want us to stop here, okay? Now, this multiplication is very important as well. Now, the first step is division, okay? So, we are going to try and use nine to divide. Since nine is Since this nine is one digit, we try and use it and divide this four digits here, okay? And since it's not possible, we'll now include the second digit, okay? So, how many nine can we find inside 21? How many nine can we find inside 21? Now, let's check from our multiplication. We'll have nine here. We'll have 18, okay? And we'll have 27. But, 21 is closer to 18. Did you get that? 27 is closer to 18 because 20 21 is closer to 18 because 27 is more than 21, okay? So, we are going to take that we are going to see two nine inside 21, okay? So, write that two here.
That two here, okay? And then multiply.
Remember we divided and got two. The next next step is multiplication. 2 * 9 is 18, okay? Now, the next step is subtraction, then we'll subtract. Now, from here, 21 - um 21 - 18 will give us three, okay?
We'll write that three here, okay? Now, because nine is not going to divide um three and there's no number for us to bring down here, we are going to uh include zero here, okay? We are going to write zero here. And when we write zero, we'll write a decimal point here, okay?
We write a decimal point here because we wrote zero here. Now, from now now we can now divide, okay?
So, nine divide 30 and we'll come to our multiplication and check this number.
Now, we have 30 here. We have nine, 18, and 27. Now, 30 is closer to 27 and 36 is more than 30, okay? So, we are going to stop here. We have one, two, three.
So, it means that we can find three um nine inside 30, so we'll write that three here.
Okay? We'll write that three here.
Now, we'll multiply. 3 * 9 is 27, then we'll subtract, okay? Now, 30 - 27, we are going to have three, okay? We are going to have three, then we are going to bring down zero again. We'll include zero again because there's no number for us to bring down here, okay? Now, 30 / 9, we'll still have three, okay? So, write three again here and multiply. 3 * 9 is 27 and we'll subtract, okay? Now, 30 - 27 will still give us three. So, if we continue, we are going to have 3 3 3 3, okay? So, this is a reoccurring uh a decimal. It's a reoccurring decimal. We keep writing three three three. If you use your calculator, you'll see that you have 2.3333 in that category because it's a reoccurring decimal. So, it simply means that 21 divide by 9 will give us 2.333, approximately 2.3333, in that category, okay? Now, if you want to write this in a mixed fraction, it means that 21 divide by 9 will give us two whole number 3 divide by 9, okay? So, this is the decimal number and this is the mixed fraction, okay? So, whichever answer you think that is the correct answer, you can take that. So, it means that from our question, which is -3 ^ 2 + 33 - 3 divide by 3 ^ 2 will give us 2.33 or two whole number 3 divide by 9. Thank you so much for watching till the end.
Please, do well to share this video and share your thoughts in the comment section. Bye.
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