Fractions on a number line is the whole focus of these 3rd grade worksheets. There are ten CSI Mini Mystery Detective math cases in the pack, all with a train theme, and they cover unit fractions, fractions greater than 1 and whole numbers as fractions. It's 3.NF.A.2 practice that suits math centers, morning work and homework, and it makes good early finisher work too. You don't need to prep anything, and each case comes with its answer key.
Each page has four stretches of railroad track drawn as fraction number lines, with lettered points along them. Students count the equal parts from 0, write the fraction for each point, and cross off the suspect who has that fraction. No two fractions on a page are equal, which means every answer matches just one suspect. It's student-led marking, and the last name left on the list is the villain.
What's Inside
- 10 one-page cases. Each has four number lines with 20 lettered points to name, and every case has an answer key
- Number lines in halves, thirds, fourths, sixths and eighths, running to 1, 2 or 3
- A number line reference page you can project or copy
- Contents page, teacher instructions, a case log and a certificate
- 30 pages, black and white
The Cases
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The Midnight Mail Train - a sack of gold coins gone from the mail train
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The Stolen Steam Whistle - a golden whistle taken from a museum engine
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The Empty Ticket Box - the ticket office cash box found empty
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The Switched Signals - the royal express sent onto a side track
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The Inventor's Suitcase - secret plans swapped for a case of bricks
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The Dining Car Diamond - a diamond necklace gone when the lights went out
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The Runaway Engine - a steam engine rolling away down the hill
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The Fake Timetable - fake timetables at every station
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The Tunnel Smugglers - crates vanishing in Black Rock Tunnel
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The Last Stop - the gang boss and the last train out of town
When to Use This Resource
Cases 1 to 3 place fractions between whole numbers, and the first line in Case 1 is a simple fourths line from 0 to 1, which makes it a good first case once you've introduced fractions on a number line. Cases 4 to 6 add points that land on whole numbers, like 4/4 and 6/3. Cases 7 and 8 put most points past 1. In the last two cases some lines only show 0 and the end number, and students count the parts on their own. The pack also fits small groups, bell ringers, sub days and homeschool, and 4th grade teachers can use it for fraction review.
Grade Levels
Made for 3rd grade (3.NF.A.2). It's also useful for 4th graders who need a refresher on fractions on a number line.
Why Teachers Love Mystery Detectives
- No prep. Print a case and hand it out
- Students check their own answers as they cross off suspects
- Every number line is drawn to scale with equal parts
- There are never two equal fractions on the same page
- Black and white pages that photocopy well
Want more cases like these?
Follow Kiwiland Education to discover more CSI Mini Mystery Detective cases, no-prep math activities, and detective-themed printables for elementary classrooms.
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