Cheatography

# Fractions (Grade 8) Cheat Sheet by Rocketroses17

This is a cheat sheet for the fractions chapter in the Canadian curriculum of British Colombia of grade 8.

### How to multiply fractions

 1. If you have a mixed number fraction, turn it into an improper fraction Example: 1 1/3 x 3/6 2. Multiply your denomi­nators 1. 1 1/3 becomes 4/3 3. Multiply your numerators 2. 3 x 6 = 18 4. Put your new numerator over your new denomi­nator 3. 4 x 3 = 12 5. Simplify your (im)proper fraction 4. 12/18 6. Now you're done 5. 12/18 becomes 1 1/2

### How to divide fractions

 1. If you have a mixed number fraction, turn it into an improper fraction Example: 1 1/4 ÷ 4/5 2. Find the reciprocal of your second fraction 1. 1 1/4 becomes 5/4 3. Now multiply your new numerators 2. 4/5 becomes 5/4 4. And...m­ul­tiply your new denomi­nators 3. 5 x 5 = 25 5. Put your new numerator over your new denomi­nator 4. 5 x 5 = 25 6. Simplify the (im)proper fraction 5. 25/25 7. You're done 6. 1

### Mixed numbers into improper fractions

 1. Divide the numerator by the denomi­nator Example: 6/4 2. Write down the whole number answer 1. 6 ÷ 4 = 1.5 3. Write down any remainder above the denomi­nator 2. 1 4. Simplify your fraction (if necessary) 3. 2/4 5. Put your whole number in front of your new fraction 4. 1/2 6. You're done 5. 1 1/2

 1. Make your denomi­nators the same. To do this, find the lowest common multiple of both denomi­nators Example: 3/4 + 7/8 2. Add your numerators 1. 4 + 4 = 8. New denomi­nator = 8 3. Put that answer over your denomi­nator 2. 6 + 7 = 13 4. Simplify your fraction (if necessary) 3. 13/8 5. You're done! 4. 1 3/4

### How to subtract fractions

 1. Make your denomi­nators the same. To do this, find the lowest common multiple of both denomi­nators Example: 1/2 - 1/4 2. Subtract your second numerator from your first numerator 2 + 2 = 4, new denomi­nator = 4 3. Put your new numerator over your denomi­nator 2. 2 - 1 = 1 4. Simplify your fraction (if necessary) 3. 1/4 5. You're done! 4. 1/4

### Improper fractions into mixed numbers

 1. Multiply the whole number by the denomi­nator Example: 1 5/10 2. Add this number to your numerator 1. 1 x 10 = 10 3. Put that number over your denomi­nator 2. 10 + 5 = 15 4. Simplify your improper fraction if possible 3. 15/10 5. You're done! 4. 3/2

### Fraction terms

 Reciprocal = the result of flipping the number upside down 1/2 = proper fraction because the numerator is smaller than the denomi­nator The first or top number is the numerator. Ex. 1 in 1/4 3/2 = improper fraction because the numerator is bigger than the denomi­nator The second or lower number is the denomi­nator 1 1/2 = mixed number fraction because there's a whole number and a fraction combined to make one fraction When a shape is divided into equal sections of which some have been shaded, the amount of shaded sections is the numerator and the total amount of sections, unshaded or shaded is your denomi­nator When there is a numerator over another fraction, you divide the lower number, top number divided by bottom number and then you divide the numerator by the new denomi­nator

### How to simplify fractions

 1. Write down the factors of the numerator and the denomi­nator until you find the lowest common multiple Example: 6/4 2. Determine what the lowest common multiple is 1. 2, 6, 12 2, 4, 8, 12 3. Divide the numerator and the denomi­nator by their lowest common multiple 2. 2 4. Write down the new simplified fraction 3. 6 ÷ 2 = 3 and 4 ÷ 2 = 2 5. You're done! 4. 3/2