3.NF.2: Place Fractions on a Number Line
Also written as 3.NF.A.2 and CCSS.MATH.CONTENT.3.NF.A.2 · Cluster: Develop understanding of fractions as numbers.
The Official Wording
Understand a fraction as a number on the number line; represent fractions on a number line diagram.
Common Core State Standards, Grade 3, Number & Operations: Fractions · Read it at the source · Checked October 14, 2026
What 3.NF.2 Means in Plain English
Third graders treat a fraction as a point on the number line, not just a shaded shape. To show 3/4, they mark 0 and 1, cut that length into 4 equal jumps, and count three jumps from 0. The end of the third jump is 3/4.
Part a places one unit fraction such as 1/4 by splitting the 0 to 1 interval. Part b stacks copies of it to reach 3/4 or 5/4. The number line is where equivalence and comparison happen next (3.NF.3), and where 4th graders add fractions and place decimals (4.NF.6).
3.NF.2 I Can Statements
- I can split the space from 0 to 1 into equal parts.
- I can find 1/4 on a number line and explain why it belongs there.
- I can mark 3/4 by counting three fourths from 0.
3.NF.2 Worked Example
Three fourths, built on a number line the way part a and part b describe it: first the unit fraction, then three copies of it.
Draw a number line from 0 to 1 and mark the point 3/4.
- Draw the line and mark 0 and 1. The distance between them is the whole, and every fraction is measured against it.0 and 1 marked, the whole is the space between
- The denominator is 4, so cut the whole into 4 equal pieces. Three tick marks do it, and each piece is the same length.4 equal parts, 3 ticks between 0 and 1
- The first tick is one fourth of the way from 0, so it is the number 1/4. That is part a.first tick = 1/4
- Now 3/4. Start at 0 and jump three fourths: one fourth, two fourths, three fourths. Where the third jump lands is 3/4. That is part b.three jumps of 1/4 land at 3/4
- Label every tick, not just the answer, so the line reads like a ruler.0, 1/4, 2/4, 3/4, 1
Check it: One more jump of 1/4 should land exactly on 1, since 4/4 is the whole. If it overshoots or falls short, the parts were not equal.
Common Mistakes with 3.NF.2
Counting tick marks instead of spaces
Four tick marks drawn between 0 and 1 for fourths, so the line is really in fifths
Try this: Have students count the jumps, not the marks. Fourths means four spaces, which takes three tick marks between 0 and 1.
Unequal parts
0 to 1 cut into 4 pieces of visibly different lengths, with 1/4 at the first tick
Try this: Fold a paper strip the same length as the whole into fourths and lay it under the line to place the ticks.
The whole is the whole line
On a line from 0 to 2, 1/2 marked at 1 because 1 is halfway across the paper
Try this: Circle the 0 and the 1 first. The whole is always the distance from 0 to 1, no matter how long the line is.
Where 3.NF.2 Fits
Practice 3.NF.2
Quick Check
- A number line from 0 to 1 is cut into 6 equal parts. What fraction is at the second tick after 0?
- How many tick marks go between 0 and 1 to show eighths?
- On a number line from 0 to 2 marked in fourths, where is 5/4?