This is the video for lesson 59 on my web site. Place value to billions and more practice rounding. In previous lessons, we worked at place value. What we’ll do in this lesson is extend that so that we’ll be able to handle very large numbers. Let’s review what we’ve learned about place value in previous lessons and then we’ll go ahead and extend it. Now in any number the right most digits is always call the 1 place. It’s considered to be in the 1 place and we know it numbers like that look like just a single digit. Moving to the left, we have the 10’ place, 10 times as big as the 1 place. In numbers, they are look like this. Two digits, 100’s are three digits. We’d work with this in previous lessons. In thousands, we have four digit numbers and notice how I have to put a comma. This is just what we do in math. We put a comma in between the thousands place and the hundreds place.

Every three spaces as we move to the left, we’ll put a comma. Ten thousands, five digit numbers that look like that. Hundreds thousands, as we move to the left each place value is ten times as big as the one on the right. Now on the screen I've ran out of rooms, so what I've done is I moved to the next line. Pretend that we’ve moved to the left, to the left of hundred thousands. Ten times bigger than a hundred thousand is a million and that’s a seven-digit number and it looks like that, I have to put a comma to the left as we move to the left in between eery after every three digits. We have to put a comma just to make it easier to read. Ten millions is an eight digit number it looks like this. Hundred millions, nine digits and finally billions is a ten digits numbers, and were going to need an extra comma that helps us too really see that it's billions.

Okay, one of the things that you maybe asked to do is round one of this large numbers in a particular way. So I'm going to write a very big number. Let me write in and then we can figure out what this number actually is. It's very big number but the commas help us figure out what number it is. We can see that it's ten digits. It actually extends to the billions place. So we would say that these numbers 9,263,456,782. Okay, let’s say you were asked to round this number to the nearest hundred million. Now recall what we’ve done in previous lessons. First, we locate the place that were rounding too, that’s this, that’s in hundred millions places according to our chart. And then we look at the digit to right of it. If it's five or higher, we round up. if it's four or lower, we leave the digit that’s to the left of it just the way it is.

In this case, it's five or higher and so were round up and our new number will become 9,300,000,000 the rest of the way. So the number will be simply read as 9,300,000,000. Okay, this is just a basic lesson helping us extend the place value chart to billions and a little bit more rounding. Make sure that you feel fully comfortable with these large numbers. I know that they don’t come up that often in everyday life but they do come up often in math. So make sure that you can fully recognise these large numbers. We’ll work with them more later.