Estimating multi-digit division word problems | Grade 5 (TX TEKS) | Khan Academy

We're told a dog food company produced 4,813 dog biscuits. The company will put the dog biscuits into bags, each containing 40 biscuits. About how many bags will the company be able to fill? So pause the video and think about it, and remember you don't have to figure out exactly how many bags the company will be able to fill; they say about how many bags.

All right, now let's work through this together. To figure out this, I'm just going to round some of these numbers so that I can work with them in my head. So, 40 is already a nice, clean, friendly number. Let's see, I'm going to have to divide this number by 40. If I divided 4,813 by 40, I would get the exact number of bags that the company would be able to fill. But maybe I could round this to something that is very easy to divide by 40.

If I round this to the nearest 100, that gets me to 4,800. So I can say this is going to be approximately equal to 4,800 divided by 40. Why did I like 4,800? Well, because 4 goes into 48 really cleanly. So let's see, how many times does 4 go into 4,800?

4 goes into 48 12 times, so it goes into 4,800 1200 times. Therefore, 40 would go in 120 times. So I would say approximately 120 bags.

Let's do another example. A teacher is taking 29 students on a field trip to the state fair. The teacher has 592 tickets for the rides and games. She wants to divide up the tickets equally among the students. Estimate the number of tickets each student will get.

So again, pause the video and try to do that. All right, so neither of these numbers are really that friendly. But it looks like we can round them to numbers that are a little bit more friendly. So, 29 is approximately 30, and then 592 is approximately 600.

If I round to the nearest 100, 600 are nice, friendly numbers. 30 goes into 600 pretty cleanly; 600 divided by 30 would be 20. So, approximately 20 tickets per student.