When two fractions have the same numerator, you have the same number of parts. Now the size of each part decides. More equal parts means smaller parts.
So 3/5 is greater than 3/8. Fifths are bigger than eighths because the whole is cut into fewer pieces. This can feel back to front: the smaller denominator gives the bigger fraction, when the numerators match.
Fraction strips of the same length make this easy to see: line them up and compare the shaded lengths.
Worked example
Which is greater: 2/3 or 2/7?
- Both have 2 parts.
- Thirds are bigger than sevenths, so 2 thirds is more.
Answer:2/3
Key words
- same numerator
- the same number of parts
- size of a part
- smaller when the whole has more parts
- less than (<)
- smaller than
Practise this
New questions every time.
Common Core-referenced: 3.NF.A.3d