2-Digit Addition & Subtraction with Regrouping

Inside the case file

These two digit addition and subtraction with regrouping worksheets give your 2nd grade class ten CSI Mini Mystery Detective math cases with a spy theme. Every page mixes addition with regrouping and subtraction with regrouping, which makes it 2.NBT.B.5 practice for math centers, morning work or homework. There's no prep, and every case has an answer key.

Each case has 16 problems: eight of two digit addition and eight of two digit subtraction with regrouping. Every addition needs regrouping as well. Students solve a problem, find the suspect whose ID badge matches the answer, and cross that suspect off. If the work is right, only one suspect is left, and that's the villain. The common slips, like forgetting to carry the ten or taking the smaller ones digit from the bigger one, don't match any badge. A student whose answer matches nobody goes back and works that problem again.

What's Inside

• 10 one-page spy cases with 16 problems each, 160 problems in all
• An answer key for every case
• Every problem needs regrouping. Sums are 99 or less, and every subtraction answer is a two digit number
• Addition and subtraction mixed together on each page
• A How to Regroup page with one worked addition and one worked subtraction, set out in tens and ones
• Teacher instructions, a contents page, a Detective's Case Log and a Top Secret Agent certificate
• 30 pages, made to print in black and white

The Cases

1. The Missing Secret File - a top secret file gone from Spy Headquarters
2. The Stolen Spy Camera - a pen camera missing from the gadget lab
3. The Vanished Binoculars - night vision binoculars taken from a rooftop lookout
4. The Missing Golden Key - the key to the spy vault
5. The Cracked Code Lock - a gadget closet left wide open
6. The Stolen Agent Badge - a badge taken from the Spy Academy wall
7. The Missing Treasure Map - the map to a secret meeting spot
8. The Bugged Phone - a listening bug hidden in the hideout phone
9. The Lost Spyglass - a spyglass taken from the lighthouse
10. The Stolen Fingerprints - fingerprint cards from the spy lab

When to Use This Resource

Use this pack after your 2nd graders have learned to regroup in both addition and subtraction, because each page has both on it. The How to Regroup page can go on the board or in a math folder for students who need the steps in front of them. A single case works for a small group, a bell ringer or a sub plan. In 3rd grade, the cases make a regrouping review before you move on to three-digit numbers. They also suit homeschool practice and intervention groups.

Grade Levels

This pack is for 2nd grade, where 2.NBT.B.5 asks students to add and subtract within 100 using place value. 3rd grade teachers can use it for review and for students who are still unsure about regrouping.

Why Teachers Love Mystery Detectives

All Mystery Detective packs follow the same routine. After one case, your class knows how the next one works, whichever pack it comes from. The cases don't depend on each other, and you can pick the one that fits the day. Naming the villain gives students a clear finish, and the answer key makes checking a page quick.

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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