Rounding Whole Numbers CSI Mystery Worksheets

Inside the case file

Rounding whole numbers worksheets, rounding to the nearest 10 and 100 practice, rounding to the nearest 1,000, and place value activities for 3rd grade, 4th grade and 5th grade are all included in this CSI Mystery Detective. Students round their way through five pieces of evidence to work out which cash bag was taken from the bank vault - perfect for math centers, morning work, early finishers, sub days, homework, small-group intervention and test prep review. Completely no prep - just print and go.

A cash bag has gone missing from City Central Bank. The vault door was locked, the alarm never sounded, and the collection sheet has been soaked through. Fifteen bags are listed in the register and only rounding will say which one is gone.

What's Inside

• Rounding whole numbers to the nearest 10, 100 and 1,000, and to the nearest 10,000 on the bank's five-digit takings
• Rounding an amount and matching it to the record it belongs to in the vault register
• Auditing a clerk's rounded figures and stamping each one correct or wrong - the mistakes are the ones students really make, from digits chopped straight to zeros to a 5 sent the wrong way
• Marking a number on a number line between two benchmarks and deciding which way it rounds
• Rounding run backwards - working out which amounts a witness could be describing when all they remember is the rounded figure
• Reading place value in a rounded answer to crack the final code
• Tracing a route through the bank floor plan, leaving each room by the door showing the right answer

One case, five clue pages, and a suspect chart that narrows fifteen cash bags down to one. Color and black-and-white versions of every page, and answer keys throughout.

What is a CSI Mystery Detective?

It's a print-and-solve math activity - like an escape room without the locks. Students work through math problems to collect evidence, eliminate suspects, and reveal who did it. It combines real skill practice with critical thinking and a detective hook that keeps the whole class engaged.

When to Use This Resource

• Math centers and rotations
• Morning work and warm-ups
• Early finishers
• Sub days and emergency plans
• Homework and spiral review
• Small-group intervention
• Whole-class rounding and place value review
• Test prep before state testing

Grade Levels

Designed for 3rd, 4th and 5th graders working on rounding and place value, and a particularly good fit for 4th grade. Also beneficial for struggling older students who need extra practice and advanced younger students ready for a challenge.

Why Teachers Love CSI Mystery Detective packs

• Zero prep - just print and hand it out
• The pages check themselves - a wrong answer stops the mystery in its tracks, so students go back and find their own mistake before it reaches your marking pile
• Rounding practice students actually want to finish, because they want to name the culprit
• Builds real place value understanding, not a rhyme students forget by Friday
• Prints clean in black and white
• Works for the whole class, small groups or one student on their own

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