Which course was this in? Do you have a link to the specific video or article or exercise?
The specific instructions are relevant.  I can think of many situations where rounding up would be exactly the correct thing to do, such as "If each person can exert 4kg of force on a rope, how many people need to pull on the rope to total 25kg of force?"

It is the SAT MATH course ,and i have a screen shot but I can't send it here ; it was the course challenge and the problem intge site that you can't go back to review question after moving on or finishing the test
And the answer of the question that u asked I think it have to be 7 people cause it was 6 the force is going to be 24 and we still need 1 Newton to get to 25 so another person will be more than enough! I got your point with these types of questions but my question asked about the number and it was 266.7 and there is no condition that. Said it have to be atleast 267 or something else I hope you got my point

Timpony School District surveyed a random sample of 60 middle school students about the amount of time they watch TV. Of the students surveyed, 14 average watching more than 4 hours of TV each day. There are 1143 middle school students in the Timpony School District. Based on the data, what is the most reasonable estimate for the number of Timpony School District middle school students who average watching more than 4 hours of TV each day? Here I copied the question

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abdelrhman1782008,

I would say the most reasonable estimate for a number of students would always be a whole number, so I would also round 266.7 to 267.  
How do you think it would be reasonable to say "I think 266.7 students are in this category"?

Exactly that is what I mean you can't say 266.7 students but at the same time you don't have enough to say 267 or you can't say 266 and half students 😅
So when you don't have enough you take the hole number without rounding we do this with clothes , tickets, humans any thing that can't be split in half or rounded up so the answer should be 266 without rounding or caring about the decimal

Ok, now I think I understand your view.
But what we do with non-integer results depends on the situation. Consider 4 different situations with 2667 ÷ 10 = 266.7 below.

Example A -- no rounding:
"Jiro has 2667 liters of solution to divide evenly into 10 containers.  How much solution should he put in each container?"
He can measure out fractional liters, so he puts 266.7 liters into each container.

Example B -- round up:
"If each person who comes to a concert pays $10, how many people must come to cover the $2667 cost of the concert?"
If only 266 people come, the $2660 paid will not cover the cost.  267 people must come to cover the cost.

Example C -- round down:
"Keiko has 2667 nails to use building birdhouses.  If each birdhouse requires 10 nails, how many birdhouses can she build?"
Once she builds 266 birdhouses, she only has 7 nails left and cannot build more, so 266 birdhouses is the answer.

Example D -- round to the nearest:
"Some of the students at a school with 1143 total students were surveyed about TV viewing.  1/10 of students surveyed watched more than 4 hours of TV yesterday. What is the most likely number of students in the school who watched more than 4 hours of TV yesterday?"
The answer has to be an whole number of students.  The surveyed students might have watched more TV or less TV than the rest of the students -- there is no reason to prefer rounding up or down.  Therefore, we round to the nearest whole number; the answer is 267 students.
Does that make sense? Do you agree? Do you have questions?

I thought on this question there was no condition to round up like to cover the cost or somthing so it's preferred to round down because they are humans it's like having 7 t-shirts ur gonna split them on 3 people every one will have two and one t-shirt is remaining we can't split it and there is no condition that make us round up like cost or anything
Hope you got my point and i really appreciate your effort to help

But estimating the number of instances in a population based on surveying a sample is nothing like having 7 t-shirts to split!

I don't know how else to explain it. 

Thank you for appreciating my effort.  Good luck.

Thanks for ur help I just wanted to say that this is an estimate so the estimate came In fraction so I will choose the closest in the choose;in the numerical response, I will just round it down cause the number we get from estimating is not enough for another person