Number & Operations—Fractions
Fractions as Parts of a Whole
Representing a fraction as equal parts of a whole.
A New Kind of Number
Every number used so far has counted whole objects. A fraction is different — it describes a part of a single whole that's been divided into equal-size pieces, like one slice of a pizza cut into 8 equal slices.
Definition — Fraction
For a fraction to make sense, the whole must be divided into equal-size parts — not just any parts. The denominator names how many equal parts make up the whole, and the numerator counts how many of those parts are being talked about.
Worked Example — Naming a Shaded Fraction
Worked Example — Drawing a Fraction
Tip
Common Mistakes
Dividing a whole into unequal parts and still calling them fourths or thirds, such as shading one uneven slice of a rectangle and calling it 1/4.
Every part must be exactly the same size for a fraction name to apply. Check that all parts are equal before naming the fraction.
Mixing up the numerator and denominator, such as reading 3/4 as 'four out of three.'
The bottom number is always the total number of equal parts (denominator), and the top number is always the count being described (numerator) — the bottom number never changes meaning based on the situation.
Key Takeaways
- A fraction describes equal parts of one whole.
- The denominator names how many equal parts make the whole; the numerator counts how many of those parts are being described.
- Every part of the whole must be exactly the same size for the fraction name to be correct.
Summary
Fractions describe equal parts of a whole, using a numerator and denominator. The next lesson places fractions on the number line, showing they're real numbers with their own exact locations, not just shaded pictures.
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