Order of operations examples: exponents
Exponents are near the top of the food chain when it comes to order of operations. Let's do some examples together. Created by Sal Khan.
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- I have a question. At3:33, Sal says we have multiplication and division. He proceeds to do the division first. 81 / 9 = 9. Shouldn't you do the multiplication first? 5 * 81/9? Working left to right? Because there are no Parentheses and there are no exponents. In the first video "Intro to order of operations" Sal states that you should work left to right when mult./div. and add/sub.?(36 votes)
- With PEMDAS multiplication and division are of equal importance in order of operations. If you multiply by the fraction 81/9 you would get the same answer. The reason Sal divided first was because it made the problem easier to solve, because 5 times 9 is easier than 5 times 81/9. If you don't believe me try it on your calculator and you will get the same answer either way.(17 votes)
- Having trouble trying to solve this
7+8(15-9) exponent of 2(8 votes)
- 7+8(15-9) with the exponent of 2 right? first follow BEDMAS/PEMDAS or whatever order of operations you use, first comes brackets/ parentheses so you solve 15-9 which is 6 so it should be 7+8*6 with still the exponent of 2 oh and btw its multiplication because if there is no operation there and there is a bracket beside the number that is basically the multiplication sign! anyways moving on exponent goes next so since 6 with the exponent of 2 is 36, you should write 7+8*36 then you simple multiply 8 * 36 that gets you 288 so 7+ 288 will equal to 295. hopefully that helped you if not srry im not that good at explaining things XD but the answer should be 295 :)(2 votes)
- Would like more examples like these(12 votes)
- You can call this Please Escape My Dead Anaconda Snake, this is a very funny way. Its my favorite one.(11 votes)
- you mean play escape the dyinng anaconda snake(0 votes)
- I made up this one Please Eat My Delicious Artichoke Soup(7 votes)
- I didin't learn about exponents yet so that makes doing the exercises much difficult does anyone where i could learn that(4 votes)
- I have a question you see the 1+5*81/9,what do we do with the 81?(5 votes)
- I dont think he is going to answer you, because the video is kinda old.(3 votes)
- why is the distributive property not used for the ones with exponents and parenthesis?(5 votes)
- Because you'd get the wrong answer then. You use the distributive property when you have a number to multiply inside the parentheses, not an exponent.(1 vote)
- Does a negative plus a negative equal a positive?
I think I know the answer, I just need a refresher.(4 votes)
- No. Say you are 4 dollars in debt, but then suddenly you go for more dollars into debt. Then you would not have no debt-instead you would be in 8 dollars of debt. If you are doing multiplication, however, then yes, they would turn into a positive.(2 votes)
- i don't get it so what am i doing rong i just dont get itcan you please help(4 votes)
So I have six different expressions here, and what I want you to do is pause this video and try to calculate the value of each of these expressions. I'm assuming you've given a go at it. Now let's work through them. So when we see something like this, we have to remember our order of operations. We have 2 times 3 squared, and we have to remember that the first thing we would need to think about are the parentheses. I'll just write paren for short. Then we worry about exponents. Then we will worry about multiplication and division, and actually let me write it this way. We worry about multiplication and division. And then we worry about addition and subtraction. So in this expression right over here, there are no parentheses, so we do the exponents first. So we calculate what 3 squared is. 3 times 3 is 9, so this becomes 2 times 9, which is equal to 18. Now let's look at this one, and this one is interesting, because they have-- it looks like the same expression, but now there are parentheses. And because of these parentheses, we're going to do the multiplication before we take the exponent. So 2 times 3 is going to be 6, and we're going to take that to the second power. So that's 6 times 6, which is equal to 36. Now let's think about this one right over here. Once again, we want to do our multiplication and our division first. So we have a division right over here. 81/9 is the same thing as 81 divided by 9, and that's going to be 9. And then we have-- so it becomes 1 plus 5 times 9. Now we want to do the multiplication before we do the addition, so we're going to do our 5 times 9, which is 45. So this becomes 1 plus 45, which of course is equal to 46. Now let's tackle this one right over here. So, we would want to do the exponents first. So, 1 squared, well that's just going-- let me do this in a different color. 1 squared is just going to be equal to 1, so that's just going to be equal to 1. And so you have 2 times 4 plus 1. What should you do? Should you add first or do the multiplication first? Well multiplication takes precedence over addition, so you're going to do the 2 times 4 first. 2 times 4 is 8, so you're going to have 8 plus 1, which of course is equal to 9. Now you have a very similar expression, but you have parentheses. So that's going to force you to do what's in the parentheses before you take the exponent. But within the parentheses we have multiplication and addition, and we have to remember that we do the multiplication first. So we're going to do the 2 times 4 first, so that's going to be 8 plus 1 to the second power. 8 plus 1 is 9, so that's 9 to the second power. 9 squared is the same thing as 9 times 9, which is equal to 81. Now we have one more right over here that looks very similar to this one, except, once again, we have parentheses that's making us do the addition first. Without parentheses, we would do the multiplication and the division first. But here, we see that 1 plus 5 is 6, and then we have this 81/9, which is 9. So this simplifies to 6 times 9, which of course is equal to 54.