Problem Set 18 – Like and Unlike FractionsClass 5 Maths · Chapter 5 Fractions · Problem Set 18 – Maharashtra Board

Summary: Problem Set 18 – Like and Unlike Fractions

Fractions with the same denominator, such as 2/9, 5/9 and 7/9, are called like fractions.

Fractions with different denominators, such as 1/4, 2/5 and 5/6, are called unlike fractions.

To make unlike fractions like, find a number that is a multiple of every denominator — a common multiple.

Then change each fraction into an equivalent fraction with that number as its denominator.

If one denominator is a multiple of the other (like 3 and 9), the bigger one can be the common denominator. Otherwise, multiplying the denominators always works.

Key points to remember

• Like fractions: same denominator
• Unlike fractions: different denominators
• Common denominator = a common multiple of the denominators
• List multiples to find one: 4 → 4, 8, 12…; 6 → 6, 12…
• Multiply top and bottom by the same number
• If 9 is a multiple of 3, use 9
• Product of denominators is always a common multiple
• 3/4 and 5/6 → 9/12 and 10/12

Problem Set 18 – Like and Unlike Fractions – Notes

1. Like and unlike fractions

• Like fractions have equal denominators: 1/5, 3/5, 4/5.
• Unlike fractions have different denominators: 2/3, 3/7, 5/8.
• Like fractions are easy to compare, add and subtract, so we often change unlike fractions into like ones.

2. Finding a common denominator

• Write a few multiples of each denominator.
• Pick a number that appears in both lists. The smallest one keeps the numbers small.
• For 4 and 6: multiples of 4 are 4, 8, 12, 16…; of 6 are 6, 12, 18…; 12 is in both.

3. When one denominator is a multiple of the other

• 2/3 and 5/9: 9 = 3 × 3, so use 9.
• Only 2/3 needs to change: 2/3 = 6/9. The fraction 5/9 stays as it is.
• The like fractions are 6/9 and 5/9.

4. The 'multiply the denominators' trick

• For 1/4 and 2/5, the product 4 × 5 = 20 is a multiple of both.
• 1/4 = 5/20 and 2/5 = 8/20.
• Other common multiples like 40 or 60 also work, but the fractions become bigger.

5. Checking your work

• Each new fraction must be equivalent to the old one — divide back to check.
• 9/12 ÷ 3 on top and bottom gives back 3/4. ✔
• All the new fractions must have the same denominator.

Formulas at a glance

Key terms

Problem Set 18 – Like and Unlike Fractions – Flashcards

Read the question, answer it in your head, then tap the card to check. 10 cards.

Problem Set 18 – Like and Unlike Fractions – MCQ Quiz

10 questions. Tap an option — you will see at once if it is right and why.

How to study Problem Set 18 – Like and Unlike Fractions

⏱ About 25 minutes

1. Learn (5 min)
   Learn the meanings of like and unlike fractions and common multiple.
2. Practise (15 min)
   Write multiples to find common denominators, then do the 4 'Try it yourself' sums.
3. Review (5 min)
   Check by dividing back, then take the quiz and play 🎮 Play.