Rounding Whole Numbers CSI Math Mystery Worksheets | Grades 3–5 | The Bank Heist

Rounding is the only tool students get in this locked-vault case — they round to the nearest 10, 100, 1,000 and 10,000 across five pieces of evidence, crossing cash bags off the register one clue at a time until only the stolen one is left. No prep, printable and self-checking, it suits math centers, morning work, early finishers, sub days, homework, small-group intervention and test prep.

Quick Details

Skill: Rounding whole numbers to the nearest 10, 100, 1,000 and 10,000 · Grades: 3–5 · Format: One full case, 5 clue pages + complete answer keys (printable PDF, color and black-and-white) · Theme: The Bank Heist

The Case

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.

The 5 Clues

Clue One — The Vault Register — Students round each amount to the place it names, find their answer in the register, and the letters beside it spell the clue in order.

Clue Two — The Night Audit — The clerk rounded the takings from ten branches; students round each one themselves and stamp the line CORRECT or ERROR, and whichever stamp wins names the color of the bag.

Clue Three — On the Number Line — Students mark each number on its line with an X and round it; more rounded up or more rounded down decides the fabric of the bag.

Clue Four — The Two Witnesses — Each witness remembers the amount only as a rounded figure, so students circle every amount both descriptions could fit, and the count decides the size.

Clue Five — The Floor Plan Maze — Students round the number in each room to the place it shows and leave by the door with that answer, tracing the thief's route from IN to END.

Why Teachers Love It

Zero prep — print and teach. The audit page is built from the mistakes students really make, so finding the errors is the practice, and because every page is self-checking a wrong rounding visibly breaks the puzzle. Five different puzzle formats keep a single skill from feeling repetitive.

Skills Covered

Rounding whole numbers to the nearest 10, 100, 1,000 and 10,000, placing numbers on a number line to decide which way they round, checking someone else's rounded figures, and reasoning backwards from a rounded amount to the numbers it could have been — plus logical reasoning and deductive elimination as students rule suspects out clue by clue.

What's Included

A story page that sets up the case, five printable clue worksheets, the suspect chart of fifteen cash bags, complete answer keys and clear student instructions — every page in full color and in an ink-saving black-and-white version, all in one PDF.

Best Used For

Math centers and rotations, morning work, homework, early finishers, substitute and relief days, small-group intervention, spiral review and test prep for Grades 3–5.

More From This Line

Browse every CSI Math Mystery, or pair it with The Three-Digit Suspect and 3rd Grade Review.