If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

### Course: 5th grade>Unit 2

Lesson 1: Common fractions and decimals

# Common fractions and decimals

Build intuition behind memorizing the decimal form of common fractions like that 1/2 equals 0.5 or 3/4 equals 0.75.
Some fractions are so common that it's worth memorizing the decimal form. Here are a few of the most common fractions and their decimal forms:
start fraction, 1, divided by, 2, end fraction, equals, 0, point, 5, space, space, space, space, space, space, space, space
start fraction, 1, divided by, 4, end fraction, equals, 0, point, 25, space, space, space, space, space, space, space, space
start fraction, 1, divided by, 5, end fraction, equals, 0, point, 2, space, space, space, space, space, space, space, space
Sweet. Now that we know these three common fractions, let's use them to convert other fractions to decimals and decimals to fractions.

## Practice 1: Converting from fractions to decimals

Convert the following fractions to decimals. Don't use a calculator! The goal is to be able to figure these out quickly in your head.
start fraction, 1, divided by, 2, end fraction, equals

start fraction, 1, divided by, 4, end fraction, equals

start fraction, 2, divided by, 4, end fraction, equals

start fraction, 3, divided by, 4, end fraction, equals

start fraction, 1, divided by, 5, end fraction, equals

start fraction, 2, divided by, 5, end fraction, equals

start fraction, 3, divided by, 5, end fraction, equals

start fraction, 4, divided by, 5, end fraction, equals

## Practice 2: Converting from decimals to fractions

Convert the following decimals to fractions. Just like in the last section, please try to do these in your head.
0, point, 2, equals

0, point, 25, equals

0, point, 4, equals

0, point, 5, equals

0, point, 6, equals

0, point, 75, equals

0, point, 8, equals

## Want to join the conversation?

• How can you tell what decimal is what fraction
• A decimal can be recognized by looking at what place the digit is to the right of the decimal point. I'll use 0.4 as an example. The four is in the tenths place, meaning the four would be placed above a ten: 4/10. When it's simplified, it's 2/5. This is that decimal expressed as a fraction.

The same is for 0.05. The five is now in the hundredths place, meaning there is a hundred below the five: 5/100. When simplified, it's 1/20.
• What if the fraction or decimal is harder?
• Fractions don't get harder, they get bigger.
Let's say I want to convert 0.32845 to a fraction. Since the 5 ends in the hundred thousandths place, I would place the 32845 over 100,000. I would then simplify, dividing by the common factor 5, and get the final answer, 6569/20,000.
• are decimal related to fraction??
• yes, decimals and fractions are related to each other, like you would call 0.3 as "three tenths", which is a fraction.
• what are some decimals i need to memorize
• Working through the practice problems should give you a set of common fractions and decimals. Here are a few you should understand or at least memorize:

Fraction >>> Decimal
1/10 >>> 0.1
1/4 >>> 0.25
1/3 >>> 0.34 (or 0.3333333 repeating 3)
1/2 >>> 0.5
• How do u keep yourself from forgetting decimals and fractions without needing to practice them ALL THE TIME. ( or how long does it take to be fully fluent with fractions and decimals?
• I remember when I was learning this it was difficult for me, but now after a while I have become fluent with the fractions and decimals shown in the article.
So just practice and try hard and you can become fluent with them as well; just remember that everyone goes at their own pace, don't be too hard yourself.
• Who came up with math?
• what type of pepole decided that math was a good idea?! like i know that we use it every day BUT MATH IS HARD:(
• How to convert a fraction into a decimal?