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.

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?
• If the fraction or decimal is harder, then divide the numerator from the denominator really quickly.
• 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.
• 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:(
• 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
• pretty easy if you pay attention
• Yeah I agree to
• How to convert a fraction into a decimal?