Dividing 2-digit numbers by 2 digit-numbers | Grade 5 (TX TEKS) | Khan Academy

Let's get a little bit of practice dividing with two-digit numbers. So, let's start by trying to figure out what 92 divided by 23 is. Pause this video and see if you can figure that out.

All right, now let's work through this together. So, I am going to rewrite this. We're going to see how many times 23 goes into 92. So, the first thing that I want to do, I just say, "Well, okay, 23 goes into 92." Let's think about it.

23 is roughly 20; 92 is roughly 90. So, 20 times 4 would be 80; that seems pretty close. 20 times 5 would be 100, so that goes over 90. I'm going to try four here; let's see if that works out. Four times 3 is 12; four times 2 is 8 plus 1 is 9. That worked out nicely. Four times 23 is exactly 92. I have no remainder.

So, there I have it: 92 divided by 23 is equal to 4. Let's do another example. Let's see if we can figure out what 86 divided by 15 is. Pause the video again and see if you can have a go at that.

All right, so again I will rewrite it. 15 goes into 86. All right, so here I'm going to have to estimate again. 86 is a little bit less than 90. 15 times 2 is 30; 15 times 4 is 60; 15 times 6 is 90, so that gets us too high. It's going to be a little bit less than that.

So, let me just try 15 times 5, or let me see if 15 goes into 86 five times. Five times 5 is 25; 5 times 1 is 5, of course, plus 2 is 7. This is looking right, and then I have a remainder here.

6 minus 1 is, sorry, 6 minus 5 is 1; 8 minus 7 is 1, and 11 is less than 15, so I can't divide into it anymore. So, this is 5 with a remainder of 11.

The key when you're dividing by two-digit numbers like this is to try to estimate, and there is a little bit of an art to it. You're going to have to say, "Okay, well let me just try some number out." Maybe it's a little bit too low; maybe it's a little bit too high, and you're going to have to do a little bit of trial and error, but that is okay. That is the way that everyone does it.