Welcome to Math with Mr. J. In this video I'm going to show you how to convert a fraction to a decimal and if you take a look at the top of your screen it says divide the numerator by the denominator and round if needed. So that's exactly what we are going to do. Now I'm going to do a few of these by hand, a long division problem to show you exactly what's going on. And then the others, I will give you the answer that a calculator will give you and show you how to interpret everything.
So let's jump right into number one, where we have two fifths or two over five. So here, again, divide the numerator by the denominator. So two divided by five. And this fraction is less than a whole.
So our decimal is going to be less than a whole as well because. This decimal is going to be equivalent to two-fifths. So we can't do two divided by five, right? We can't take a whole group of five out of that two. So we need to extend our division problem by putting a decimal and a zero.
So now we can think of that as 20. Bring our decimal straight up. How many whole groups of five can we pull out of 20? Well, four. 4 times 5 is 20. Subtract and we get a 0 and that tells us we are done. So 2 5ths is equal to 4 tenths.
Number 2, 9 25ths. I'll do this one by hand as well. So 9 divided by 25. So we need to Extend our division problem with a decimal and a zero because we can't do 9 divided by 25 and get a whole number. We can't pull a group of 25 out of 9. So now we think of this as 90. How many whole groups of 25 out of 90? Well, 3. 3 times 25 is 75. Subtract, we get 15. So we did not get a zero right away like number one.
So we can extend this division problem by putting another zero on the end. A zero to the right of a decimal doesn't change the value. So we're not changing the problem at all.
Now we can bring that zero down. And we have 150 divided by 25. And we can pull six whole 25. Out of 150, 6 times 25 is 150, and we get that clean-cut zero. So we do not need to go any further. We are done.
And that problem kind of ran into the top problem there, but our answer is 36 hundredths. So 9 25ths is equal to 36 hundredths. Let's take a look at number 3. Now number three, if we were to plug in three over three divided by 16 into a calculator, we would get the following decimal.
And it goes to the ten thousandths. So it's typical to either round a decimal to the thousandths or hundredths. So we're going to round to the thousandths in this video. So we would.
take a look at what's in the thousandths. Look next door. That five says round up. We are closer to 188 thousandths. So our rounded answer would be 188 thousandths.
So that rounding step depends on what you're doing with the problem. Maybe you wouldn't round that decimal depending on the situation. And as we'll see with number four and five, we can have decimals that are much longer than just to the ten thousandths place. So speaking of number four here, we have one over three or one third.
And I'm going to show you this by hand and hopefully you'll notice a pattern as I start doing this one. So one divided by three. So again, this is just like number.
one and two where we wrote them out we can't pull a whole three out of that one so we extend with a decimal and a zero bring that decimal straight up so we look at it as as a 10. So how many whole 3's can we pull out of 10? Well 3, that gets us to 9. 3 times 3 is 9. Subtract, we get 1. Remember we want that clean-cut zero to tell us that we are done. So we need to add another zero, drop it, so we have another 10. How many whole 3s out of 10?
Well, 3. 3 times 3 is 9 and our pattern is going to start here. Subtract, add another zero and drop it, so we have another 10. 3 3s out of 10. 3 times 3 is 9. subtract a 1 and you're probably getting the point here. It's going to go on forever so it's a repeating decimal.
So our answer this is one we would want to round and if we round it to the thousandths we have a 3 there look next door it says stay the same so our answer is 333 thousandths Or, if you have a repeating decimal, You can write whatever number is repeating and put a bar over it. And that bar signifies that that digit just repeats. Okay, so two ways to do that. You can round it off or the bar shows that that digit repeats.
So number five, we actually have an improper fraction. So this is going to be above one whole. It's greater than a whole. So if you...
plug 17 over 11 or 17 divided by 11 in on a calculator you're going to get 1 54 54 54 and it's just going to be 54s repeating so again we can round to the thousandths so a 5 there look look next door that says that four says stay the same so our rounded answer would be 545 thousandths so one and 545 thousandths or we can use the bar method. I forgot to circle my answers for number four there, just notice that. Or we can use the bar method, so one and a 54 repeats, so we can put our bar above the 54 to show that that will continually repeat. Number six, 17 over 20, so 17 divided by 20 is going to give us 85. hundredths. So it cuts off in the hundredths place so no need to round.
That one works out nicely. So there you have it. There's how you convert a fraction to a decimal.
Divide the numerator by the denominator and then interpret your answer. Do you need to round? Is it a repeating decimal? Or maybe it cuts off in the tenths, hundredths, or thousandths place.
Thanks so much for watching. Until next time, peace. Thank you.