3-Digit Addition with Regrouping

Inside the case file

Halloween 3 digit addition with regrouping worksheets for 2nd grade and 3rd grade: five math sheets, each a Mystery Detective hunt for the same witch among the suspects. Print and go with full answer keys for the two weeks before Halloween, then no prep math centers, early finishers, homework and sub plans. Sixteen problems a sheet laid out in columns, every correct sum crosses one of the teachers, all suspected witches, off the lineup until one is left, so these October pages are real carrying practice, and a CSI Mini Mystery Detective checks itself.

One witch across five CSI Mini Mystery Detective math sheets is why a class comes back for the next page on their own, and by the last sheet they want to know which teacher it is. Because a wrong sum crosses off the wrong teacher, students check their carrying before they commit, and the answer keys make the whole set a five minute mark.

Who Is the Witch?

One of the teachers is not what she seems, and the class has to add their way to the truth. Every total points at a suspect and takes that name off the list, and each of the five cases has its own lineup of sixteen teachers and its own witch, so one download gives a class five separate mysteries.

What's Inside

• Five separate cases, each with its own lineup of sixteen teachers and its own witch
• Three digit addition with regrouping on every sheet
• Sixteen problems per sheet, laid out in columns
• Each answer matches one suspect and no other, so the page checks itself
• The same five cases again in black and white
• A full answer key for every case
• A set of display letters for the classroom wall
• Print and go: no cutting, no laminating, nothing to prepare

What Is a CSI Mini Mystery Detective?

A CSI Mini Mystery Detective is a single page investigation solved with arithmetic. Each suspect in the lineup carries a number, the crime sheet produces those numbers, and a correct answer takes that suspect out until one name is left. No locks, no app, nothing to assemble, which is why these detective activities get used on days that would otherwise call for math worksheets. Each case fits a class period and works in a center or a sub folder.

When to Use This Resource

October, and the closer to Halloween the better, when three digit carrying still needs practice and the class is past listening. A fresh witch to unmask on each of the five cases keeps students coming back for the next one, which is more than most seasonal worksheets manage. A dropped carry crosses off the wrong teacher, so they check the column themselves rather than handing it in and hoping.

Use it for test prep, homework, math centers, morning work, early finishers, sub plans and homeschool lessons, with a whole class, a small group or one child alone.

Grade Levels

Written for 2nd grade and 3rd grade, where three digit regrouping sits in the standards. Fourth graders take it as an October refresher, and second graders manage it once two digit carrying is secure.

Why Teachers Love These Cases

• A different witch on each of the five cases, so students want the next page
• A dropped carry takes out the wrong teacher, and students notice
• No prep in the week of Halloween
• Works with a whole class, a small group, partners, or one student alone

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