5 out of 100 students got this right! 😳 Are you among the 5?

追加: 2026-06-01

[00:00:00]And because of this division and this fraction here, a lot of students fail this particular expression, okay?

[00:00:06]Because what they did was to use this three here to divide this 15 here, and they got five, okay? Now, in their next step, they wrote 15 minus because 5 / 1 is still five.

[00:00:19]Plus 15 * 3, okay? So, from here, what they did next was to subtract, okay?

[00:00:27]They had 15 - 5, and it gave them 10 + 15 * 3, okay? Now, in their next step, they added these together. 10 + 15 gave them 25, okay? 25 * 3, okay? So, from here, the next thing they did was to multiply, and 25 * 3 will give them 75, okay? But this is totally wrong because according to the order of operation, which is PEMDAS, okay? We are going to solve this using PEMDAS, p e m d a s, okay? Where p is parentheses, e is exponent, m is multiplication, d is division, a is addition, and s is subtraction, okay? And this multiplication and division are of the same priority. That is to say, whenever you find both of them in a particular question, you have to solve from left to the right, okay? And for addition and subtraction, they are of the same priority as well. You have to solve from the left to the right whenever you have both of them in a particular question, okay? So, from our question here, we'll have we'll have division, addition, multiplication, and subtraction, okay?

[00:01:41]Now, from here, because we have multiplication and division and multiplication here, we have to solve this from the left to the right. So, we are going to attend to the division first before multiplication, okay? And looking at this division here, this involves um fraction, okay? And for us to solve it um effectively, we are going to use what is called K C F rule, okay? Where K here is keep, C here is change, and F is flip, okay? We are going to use this rule to solve this, okay? Now, from here, we are going to keep 15 and change division to multiplication and flip this. So, we write 15 minus 15, then we will write division and change it to multiplication and flip this. And remember that 3 / 1 is still 3. Plus 15 * 3, okay? Now, in our next step, we are going to multiply first. So, we have 15 minus 15 * 3 will give us 45, okay? Then plus 15 * 3. From here, remember that multiplication is of higher priority to addition and subtraction. So, we are going to multiply. We have 15 minus 45, okay? 45 plus 15 * 3 is 45, okay? So, from here, we have 15 minus um 15 minus 45 will give us 30 plus 45, okay? Now, from here, sorry, this will be minus 30, not just 30, because this one is smaller than this, okay? This 45 here is bigger than 15.

[00:03:20]So, when you subtract 15 minus 45, it will give you minus 30. So, minus 30 plus 45 will give us uh 15, okay? As the correct answer. Now, from here, let's solve another question which a lot of students was confused, okay? Now, what most students did here was to um solve it from here straight away, okay? So, from here, they divided this first and it gave them seven, okay?

[00:03:48]And we have 1 plus 4 / 2 in parentheses 3 - 1, okay? Now, in the next step, they added this four, so they have seven open square bracket 1 + 4 is 5, okay? / 2 in parentheses 3 - 1. Now, in the next step, they divided, okay? So, they had seven 5 / 2, so they wrote it as 5 / 2, okay?

[00:04:18]Then, in parentheses 3 - 1, then close square bracket. So, from here, they had this to be equal to seven, then open square bracket 5 / 2, then they introduced multiplication and subtracted this, okay? 3 - 1 is 2. So, from here, the next thing they did was to use this two here to cancel out this two, and they are left with 7 * 5, okay?

[00:04:43]And 7 * 5 gave them 35. But, this is wrong because according to the order of operation, which is PEMDAS, okay? We have to write that down so that we don't forget, okay? This is D A S, okay? And like we said earlier, this is parenthesis, this is exponent, this is multiplication, this is division, this is addition, and this is subtraction.

[00:05:06]And remember that we said that these two have the same priority, and these two have the same priority. And looking at our question, we have two different types of brackets. We have square bracket, and we have parentheses. So, the first thing we are going to do is to attend to the parentheses first, okay?

[00:05:20]So, we are going to have 14 / 2 open square bracket 1 + 4 / 2, then this parenthesis will have 3 - 2, and that is two, okay? So, we are going to introduce multiplication and write that two. Now, we are still going to attend to this square bracket, okay? So, we have 14 / 2 open square bracket, we have division and multiplication, and because division and multiplication are of same priority, we are to divide first. So, we have 1 + 4 / 2 is 2 * 2. Okay? So, from here, we have 14 / 2 open square bracket. We have 1 + 2 * 2 is 4. Okay? Because multiplication is of higher priority to add this addition here. So, we have 14 / 2 * 1 + 4 is 5. So, from here, because multiplication and division are of the same priority, we are going to divide first. 14 / 2 is 7 * 5. Okay? And 7 * 5 = 35. Now, even though we got the same answer with what the student did earlier, but because the steps are wrong, their step is wrong. So, we are going to take this one as the correct answer. Thank you so much for watching to the end. Please do well to share this video and share your thoughts in the comment section. Bye-bye.