Mathematics Topic
Fractions, Decimals, Percentages, and Standard Form
- Read notes
- Flashcards
- Quiz
- Confident
Study focus - 3 things
- Fractions, decimals, and percentages are different ways to show parts of a whole
- Percentage problems often involve converting, finding a part, or finding the whole
- Standard form writes very large or very small numbers as a number between 1 and 10 times a power of 10
Section 1Equivalent forms
Fractions, decimals, and percentages can represent the same value. For example, 1/2 = 0.5 = 50%. The key move is knowing which form makes the calculation easier.
Section 2Converting percentages
To change a percentage to a decimal, divide by 100. To change a decimal to a percentage, multiply by 100. For example, 35% = 0.35 and 0.08 = 8%.
Section 3Finding a percentage of a quantity
To find a percentage of a quantity, change the percentage to a decimal or fraction, then multiply. For example, 15% of J$2400 is 0.15 x 2400 = J$360.
Section 4Changing fractions to decimals
A fraction means division. To change 3/4 to a decimal, calculate 3 divided by 4 = 0.75. To change it to a percentage, multiply 0.75 by 100 to get 75%.
Section 5Standard form
Standard form is written as a x 10^n, where a is at least 1 but less than 10. For example, 56,000 = 5.6 x 10^4, and 0.0032 = 3.2 x 10^-3.
Examples
Convert 3/5 to a decimal and a percentage.
3/5 means 3 divided by 5 = 0.6. As a percentage, 0.6 x 100 = 60%.
Write 0.0047 in standard form.
Move the decimal 3 places right to make 4.7, so 0.0047 = 4.7 x 10^-3.
Now let's water it
Session runs notes to flashcards to quiz back-to-back.