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Rewriting fractions as decimals | Math | 4th grade | Khan Academy


2m read
·Nov 11, 2024

Let's write 29 hundreds as a decimal. So, we'll start with 29 over 100, and let's start breaking that down till we can get to place values. Because place values will help us to convert to write this as a decimal.

29 hundreds can be broken down into 20 hundreds plus 9 hundreds. 20 hundreds plus 9 more hundreds is equal to 29 hundreds. So we've just broken it down some here. It's still equivalent to 2900s; we're just taking it apart, trying to get to place values.

Going from there, we can simplify even more. 20 hundreds can be simplified; we could divide 20 and 100 by 10. So, we'll say 2 tens plus 9 hundreds. Now, if you can hear that, tenths and hundreds are place values we should recognize from decimals.

So what we've shown here is that 2900s is equal to 2 tenths plus 9 hundreds. Here we have 2 tenths, which matches 2 tenths, and 9 hundreds like our 9 hundreds right there.

We can take those and think about place value. If we have our decimal, let's first put our decimal over here. To the left of the decimal is our one's place value. We don't have any ones here, so we'll put a zero in the ones place, but then next is tenths.

Then we have our tenths, and we have 2 tenths. After the tenths is the hundreds place, and here we see we have 9 hundreds. So we'll put a 9 in the hundreds place.

So down here, 0.29, or 29 hundreds, is equivalent to the fraction 29 hundreds. Just listen to how those are said; it's kind of a clue that we did well.

29 hundreds is equivalent to 29 hundreds. Both the fraction and the decimal are read the same way, so that's a pretty good clue that we probably rewrote these correctly. So, 0.29 is equal to 29 hundreds.

Let's try one more. Let's try something. Let's say maybe 50, maybe 50 and 310. So again, we're going to break this down. We'll have 50 tenths plus how many more tenths are left? There's still 3 more tenths, and again we can simplify.

We can simplify this; 50 tenths can be divided by 10. So instead of 50 tenths, we'll say 5 ones plus we still have those 3 tenths. Now we've got this to place value.

5 ones is 5 ones plus here, 3 tenths is 3 tenths. So, thinking, let's put our decimal over here. To the left of the decimal is our ones, and we have 5 ones. To the right of the decimal is tenths, and we have 3 tenths.

So, 5.3, or 5 and 3 tenths, is equal to 53 tenths. To write 53 tenths as a decimal, we will get 5.3 because it was 5 ones and 3 tenths, which we showed right here: 5 and 3 tenths.

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