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### Course: Numbers & Operations - The Real & Complex Number Systems 211-217 > 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:

$\frac{1}{2}}=0.5\text{}\text{}\text{}\text{}\text{}\text{}\text{}\text{$

$\frac{1}{4}}=0.25\text{}\text{}\text{}\text{}\text{}\text{}\text{}\text{$

$\frac{1}{5}}=0.2\text{}\text{}\text{}\text{}\text{}\text{}\text{}\text{$

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.**

## 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.**

## Want to join the conversation?

- How can you tell what decimal is what fraction(360 votes)
- 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.(289 votes)

- What if the fraction or decimal is harder?(124 votes)
- If the fraction or decimal is harder, then divide the numerator from the denominator really quickly.(16 votes)

- are decimal related to fraction??(46 votes)
- yes, decimals and fractions are related to each other, like you would call 0.3 as "three tenths", which is a fraction.(22 votes)

- what are some decimals i need to memorize(10 votes)
- 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(30 votes)

- How to convert a fraction into a decimal?(6 votes)
- I would suggest practicing with money. If you have 1/2 dollar, how would you write that $0.50. There, you've just converted a fraction into a decimal. Now try it with a quarter (1/4) and a dime (1/10). Then try 37 cents (37/100 of a dollar).(24 votes)

- How can you memorize how to turn decimals to a fraction and fraction to a decimal(7 votes)
- The best way to memorize is to practice it often; the more you practice the better you'll memorize it.(18 votes)

- How can you memorize the conversions w/ decimals and fractions(11 votes)
- There is nothing to memorize, with a decimal put it over a hundred and simplify to convert to a fraction. And to get a fraction to a decimal divide the numerator by the denominator (divide the number on the top of the fraction by the one on the bottom).(8 votes)

- hey u add percentages and decimals :D thank you(14 votes)
- how does the fraction equal a decimal.(5 votes)
- Each fraction can be converted into a decimal one way or the other, either they can be multiplied into one due to them being factors of 10, 100, 1000 and so on. Others can be divided to convert due to them not being a factor of the numbers I mentioned. I can show you a formula for conversion of fractions: Numerator divided by the denominator = Decimal. Sure some might repeat a pattern like 1/3 being .333 and so on, so you can draw a line above the three repeated numbers and thats an infinite sign, if you've not known this before.(6 votes)

- How can you tell what denominator is the answer going to have when you convert decimals to fractions? For example, I had NO idea the 0.75 = 3/4 I though it was something else.(2 votes)
- Think of money. A dollar is $1.00, or 100 cents. A quarter (one-quarter of a dollar) is 25 cents ($0.25), because 25 cents x 4 = 100 cents.

25 cents x 3 = 75 cents, so 3 quarters (3/4 of a dollar) is 75 cents ($0.75).

We can also convert 0.75 into a fraction by writing it as 75/100, then dividing top and bottom each by 25 to get the reduced fraction 3/4.

Have a blessed, wonderful day!(9 votes)