Stage 18 of 20
Simple Fraction Mentals
Find unit fractions of whole numbers and compare simple fractions using halving, thirding, and equivalence ideas.
Unit fraction = equal share
1/2 means split into 2 equal parts; 1/4 means split into 4. For 1/3 of 24, divide 24 by 3. Keep denominators small and wholes divisible for clean mental work.
Why this mental math skill matters
Unit fractions of whole numbers connect division, sharing, and later rational-number sense. Keeping denominators small builds confidence first.
Worked examples
Study each example slowly. Say the steps aloud — verbal rehearsal strengthens mental arithmetic memory.
1/2 of 48
- Half of 48.
- 24.
Answer: 24
1/4 of 36
- Half of 36 is 18.
- Half again is 9.
Answer: 9
1/3 of 27
- 27 ÷ 3.
- 9.
Answer: 9
Tips for success
- 1/2 means equal share into two parts.
- Find 1/4 by halving twice when helpful.
- Say “of” as “times” when ready for that language.
Common mistakes to avoid
- Using wholes that do not divide evenly and getting stuck on remainders too early.
- Confusing numerator and denominator roles.
How to practice this stage
Practice 1/2, 1/3, and 1/4 of friendly wholes. Prefer numbers divisible by the denominator so answers stay whole while skills form.
Interactive practice
Stage 18 Drill
Find the unit fraction of a whole number.
Solve
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FAQ: Simple Fraction Mentals
How do you find 1/3 of a number mentally?
Divide the number by 3 when it divides evenly — for example, 1/3 of 27 is 9.
Are fraction mentals only for older kids?
Unit fractions of whole numbers can begin once division basics are comfortable; complexity can grow later.