Discover how different fractions can represent the exact same amount using pictures and math rules.
If you had a giant chocolate bar, would you rather have of it or of it? Believe it or not, they are exactly the same amount!
Equivalent fractions are fractions that look different because they have different numbers, but they actually represent the exact same value or amount. Imagine a pizza. If you cut it into 2 big slices and eat 1, you ate of the pizza. If your friend cuts an identical pizza into 4 smaller slices and eats 2, they ate . Even though your friend has more pieces, the total amount of pizza eaten is identical! We use visual models like fraction strips or circles to prove that these areas are the same size.
Quick Check
If you have a fraction bar showing , and you divide each of those 3 parts into 2 smaller pieces, how many total pieces do you have now?
Answer
6 pieces.
You don't always need to draw a picture to find equivalent fractions. You can use the Multiplication Rule. To find a fraction equivalent to another, multiply the numerator (the top number) and the denominator (the bottom number) by the same whole number. This works because multiplying the top and bottom by the same number is like multiplying the fraction by 1. For example, multiplying by is the same as multiplying by 1, which doesn't change the value, only the way it looks!
Find a fraction equivalent to by doubling the parts.
1. Start with the fraction . 2. Multiply the numerator by 2: . 3. Multiply the denominator by 2: . 4. The new fraction is .
Result:
Quick Check
To find a fraction equivalent to , if you multiply the denominator by 3, what must you multiply the numerator by?
Answer
You must multiply the numerator by 3.
Sometimes you will see two fractions that are equal, but one number is missing. To solve this, look at the numbers you do have. Ask yourself: 'What did I multiply the first number by to get the second number?' Once you find that 'secret multiplier,' use it on the other part of the fraction to find the missing value. This keeps the fraction in balance.
Find the missing numerator:
1. Look at the denominators: How did 3 become 12? 2. Calculate: . The 'secret multiplier' is 4. 3. Apply this to the numerator: Multiply the top number (2) by 4. 4. .
Result:
Are and equivalent? Prove it using multiplication.
1. Check the numerators: . 2. Check the denominators: . 3. Since both the top and bottom were multiplied by the same number (3), they are equivalent!
Result: Yes,
Which of these fractions is equivalent to ?
Find the missing number:
True or False: To find an equivalent fraction, you can add 2 to both the numerator and the denominator.
Review Tomorrow
In 24 hours, try to explain to someone why is the same as without using a drawing.
Practice Activity
Next time you eat a sandwich, cut it into 2 pieces. Then cut those into 4. Notice how of the sandwich is the same as the you started with!