Adding fractions with different denominators by first finding a common denominator.
Where your child meets this in real life: Combining different fractional quantities (½ + ¼ cups of flour)
SEAGReady breaks add fractions (different denominators) into 3 steps, taught in order so each skill builds on the last.
Add fractions where one denominator is a multiple of the other (e.g., 1/2 + 1/4)
Add fractions where neither denominator is a multiple of the other by finding a common denominator (e.g., 2/3 + 1/4)
Add fractions and simplify results or convert improper fractions to mixed numbers (e.g., 2/3 + 3/4 = 1 5/12)
Three free sample questions from our add fractions (different denominators) course. Every question comes with a full explanation, and hints that guide without giving the answer away.
Sean is making orange squash. He uses 1/2 of a jug of water and then adds another 1/4 of a jug. How much water did he use altogether?
Answer: A. 3/4 of a jug
The denominators are 2 and 4. Since 4 is a multiple of 2, use 4 as the common denominator. Convert 1/2 to quarters: 1/2 = 2/4 Now add: 2/4 + 1/4 = 3/4 Sean used 3/4 of a jug of water.
Stuck? Start here: Look at the denominators: 2 and 4. Is one a multiple of the other?
Oisin ate 1/3 of a pizza at lunch and 1/4 of the same pizza at dinner. What fraction of the pizza did he eat in total?
Answer: A. 7/12 of the pizza
Neither denominator divides the other, so find a common denominator: 3 x 4 = 12 Convert 1/3 to twelfths: 1/3 = 4/12 Convert 1/4 to twelfths: 1/4 = 3/12 Add: 4/12 + 3/12 = 7/12 Oisin ate 7/12 of the pizza in total.
Stuck? Start here: Neither 3 nor 4 divides into the other, so multiply them: 3 x 4 = 12
Roisin poured 2/3 of a bottle of juice into a jug, then added another 3/4 of the bottle. How much juice did she pour in total? Give your answer as a mixed number.
Answer: A. 1 5/12 bottles
Find a common denominator: 3 x 4 = 12 Convert 2/3 to twelfths: 2/3 = 8/12 Convert 3/4 to twelfths: 3/4 = 9/12 Add: 8/12 + 9/12 = 17/12 Convert to mixed number: 17 / 12 = 1 remainder 5 Roisin poured 1 5/12 bottles of juice in total.
Stuck? Start here: Find a common denominator: 3 x 4 = 12. Convert both fractions.
This is the exact interactive worked example your child sees in SEAGReady. Step through it and watch the method build up.
Ciara is making orange squash. She uses ½ of a jug of water and then adds another ¼ of a jug.
How much water did she use altogether?
½ + ¼
Step 1 of 5
Ciara is making orange squash. She uses ½ of a jug of water and then adds another ¼ of a jug.
How much water did she use altogether?
Ciara used ¾ of a jug of water altogether.
The key insight: When one denominator divides into the other, you only need to convert one fraction!
Watch out: ½ + ¼ = ²⁄₆. Adding numerators AND denominators separately doesn't work - the pieces are different sizes.
These are the misconceptions we see most often in add fractions (different denominators), including the ones our practice questions are specifically designed to catch.
Struggling with add fractions (different denominators)? The real gap is often in one of these earlier topics.
SEAGReady finds the exact step where your child gets stuck, teaches it with worked examples like the one above, and brings it back for review so it sticks.