CCSS.Math.Content.3.NF.A.2a
The Standard
Represent a fraction 1/b on a number line diagram by defining the interval from 0 to 1 as the whole and partitioning it into b equal parts. Recognize that each part has size 1/b and that the endpoint of the part based at 0 locates the number 1/b on the number line.
Common Core State Standards for Mathematics
Teacher's field guide
What This Standard Means
What Students Need to Do
- Students treat the distance from 0 to 1 as one whole and divide it into equal intervals. They use the denominator to determine the number of intervals and locate the first unit fraction.
What Mastery Looks Like
- Students can draw a number line from 0 to 1 and divide it into the requested number of equal intervals. They correctly label the first endpoint after 0 and explain what the denominator tells them.
Common Misconceptions
- Students may count tick marks instead of spaces, creating one too few intervals. They may use unequal spaces or label the first tick with the denominator alone.
How to Assess It
- Give students this exit ticket: “Draw a number line from 0 to 1, divide it into six equal intervals, and label 1/6.”
Lesson moves
Ways to Teach It
Tape a 0-to-1 number line on the floor, have students measure four equal intervals, then stand at 1/4.
Ask, “Why must the spaces be equal, and why is 1/5 at the first endpoint after 0?”
Give students denominator cards and number line cards, then have partners match each card to the correct unit fraction location.
Use a 60-minute timeline from 0 to 1 hour, divide it into four equal intervals, and identify 1/4 hour.
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Printable 3.NF.A.2a Worksheet
A ready-to-print activity worksheet aligned to CCSS.Math.Content.3.NF.A.2a, with an answer key for the teacher on its own page. No account needed.
PDF, US Letter, prints cleanly in black and white.
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