Convert between decimals and fractions
Key Notes :
1. Understanding the Relationship Between Decimals and Fractions
- Decimals and fractions are two different ways of representing parts of a whole.
- Both can be used interchangeably to express numbers that are less than 1, greater than 1, or equal to a whole number.
2. Converting Decimals to Fractions
- Step 1: Write the decimal number over a power of 10 (e.g., 0.5 becomes 5/10).
- The number of decimal places determines the denominator:
- 1 decimal place → denominator is 10.
- 2 decimal places → denominator is 100.
- 3 decimal places → denominator is 1,000, etc.
- The number of decimal places determines the denominator:
- Step 2: Simplify the fraction by dividing the numerator and denominator by their greatest common factor (GCF).
- Example:
- Convert 0.75 to a fraction:
0.75 = 75/100 → simplify by dividing by 25 → 3/4.
- Convert 0.75 to a fraction:
- Example:
3. Converting Fractions to Decimals
- Step 1: Divide the numerator by the denominator using long division.
- Step 2: If the division ends with a remainder of zero, the decimal is terminating.
- Step 3: If the division repeats, it’s a repeating decimal.
- Example:
- Convert 1/4 to a decimal:
1 ÷ 4 = 0.25 (terminating decimal). - Convert 1/3 to a decimal:
1 ÷ 3 = 0.333… (repeating decimal, often written as 0.\overline{3}).
- Convert 1/4 to a decimal:
- Example:
Learn with an example
Write 1/100 as a decimal number.
Write the fraction as a decimal number with 2 decimal places.
1/100 = 0.01
Write -1/2 as a decimal number.
Start with 1/2,
Write an equivalent fraction with 10 as the denominator. Then write the decimal number.
1/2 = 1 x 5 / 2 x 5
= 5/10
= 0.5
Now write a negative sign on each number:
-1/2 = -0 . 5
Write 11/20 as a decimal number.
Write an equivalent fraction with 100 as the denominator. Then write the decimal number.
11/20 = 11 x 5 / 20 x 5
= 55/100
= 0.55
Let’s practice!🖊️