Early Finishers 2-Digit Addition | Math Mystery Worksheets | Grades 1–3 | 18 Cases

Eighteen one-page cases for the child who finishes first and asks what to do now — students work the 2-digit addition problems, match each answer to a suspect, and cross suspects off until one is left standing. Every case is self-checking and completely independent of the others, so a student can pick one up cold. Eighteen is most of a term of fast-finisher work from a single print run.

Quick Details

Skill: 2-digit addition with regrouping · Grades: 1–3 · Format: 18 mysteries + full answer keys (printable PDF) · Theme: Around the school

The 18 Mysteries

The Missing Book — The last copy of the class reader is gone five minutes before silent reading.

The Vanished Ropes — Every skipping rope has gone on the morning of the skipping challenge.

The Stolen Apples — The fruit basket disappears before morning break has even started.

The Missing Boots — The garden club is due outside in ten minutes and every pair of boots has gone.

The Stolen Cupcakes — Two trays vanish twenty minutes before the bake sale opens.

The Stolen Umbrellas — The lost property bin is empty on the wettest afternoon of the term.

The Missing Scissors — The craft cupboard is bare the morning the whole grade makes paper lanterns.

The Vanished Camera — Gone from its case an hour before the class photo.

The Stolen Life Ring — Off its hook by the pool, and the swimming lesson cannot start.

The Missing Helmet — Off the rack at the gate, with the cycling group leaving after lunch.

The Vanished Bin — The recycling bin disappears on weekly count day.

The Stolen Coin Bank — Gone the day before the fundraiser money is due at the bank.

The Missing Robot — Off the workbench two days before the district challenge.

The Stolen Soup Pot — Gone an hour before four hundred lunches are served.

The Stolen Telescope — Taken on the clearest night of the whole year.

The Missing Fossil — Out of the display case with three classes about to walk through.

The Vanished Trophy — Gone the week before it is due to be handed over.

The Missing Mower — Gone the day before the field has to be cut for sports day.

Why Teachers Love It

Eighteen cases is the difference between a fast-finisher activity that runs out in a fortnight and one that lasts. Because each page is self-checking, a student can start, finish and know they were right without interrupting the group you are teaching — and the detective hook makes it read as a reward rather than more work.

Skills Covered

2-digit addition with and without regrouping — plus logical reasoning and deductive elimination as students rule suspects out clue by clue.

What's Included

Printable one-page mystery worksheets, suspect line-ups, complete answer keys with the villain marked, and student instructions — all in one PDF.

Best Used For

Early finishers and fast finishers, morning work, math centers, homework, substitute/relief days, indoor recess, spiral review, and test prep for grades 1–3.

More From This Line

Browse every Math Mystery pack, or stock the tray with Early Finishers Multiplication and 2-Digit Addition Pirate Mystery.