Addition & Subtraction Word Problems to 10,000 | Mystery Detective Worksheets | Grades 3–5

Addition and subtraction word problems, multi-digit math worksheets, and 4-digit computation practice for 4th grade are all included in this no-prep Mini Mystery Detective pack. Students solve one-step word problems within 10,000 to cross suspects off a line-up and unmask the villain in five detective cases - perfect for math centers, morning work, early finishers, sub plans, and homework. Completely no prep - just print and go.

Use it as a multi-digit addition and subtraction review before a test, a standard algorithm practice set with regrouping and borrowing, spiral review at the start of 5th grade, a no-prep math sub plan, or a station in your math centers. The problems cover all four addition and subtraction situation types, so students have to decide which operation the story calls for instead of hunting for a key word.

What's Inside

• Adding and subtracting 4-digit whole numbers within 10,000 using the standard algorithm: 3219 + 1392, 8959 - 6451, 7404 + 1675
• Regrouping and borrowing across the tens, hundreds, and thousands places on almost every problem
• Joining word problems where a starting amount grows - a recycling tally that gains more items, a fund that takes a late pledge
• Separating word problems where an amount is taken away - bottles removed from a store room, places canceled on a school trip
• Part-part-whole word problems with no action word to cue the operation - glass jars and plastic jugs counted together
• Comparing word problems - how many more and how many fewer, the situation type students most often add by mistake
• Deciding which operation a story calls for, then writing the answer in the box beside it
• Self-checking answer keys in red for every case, showing the villain and every eliminated suspect

Five school detective cases to solve: The Recycling Raid, The Fun Run Fiasco, The Museum Trip Muddle, The Coding Club Crash, and The Yearbook Blanks. Answer keys included for every case.

What is a Mini Mystery Detective?

A no-prep detective activity where students solve math problems to cross off suspects and unmask the culprit - like an escape room without the locks. Every answer matches one suspect's ID badge, so working through the page eliminates them one by one and the suspect left standing is the villain. That makes it self-checking: correct work leaves exactly one suspect, and a mistake tells students to go back and look. Skill practice plus critical thinking in one engaging worksheet set.

When to Use This Resource

• Math centers and stations
• Morning work and bell ringers
• Early finishers
• Emergency sub plans
• Homework and independent practice
• Spiral review and test prep
• Small-group intervention
• Whole-class warm-ups

Grade Levels

Designed for 4th graders. Also beneficial for struggling 5th and 6th grade students who need extra practice with multi-digit addition and subtraction, and for advanced 3rd graders ready for a challenge beyond 1,000.

Why Teachers Love Mystery Detectives

• Zero prep - just print and hand out
• Self-checking, so students catch their own mistakes instead of waiting for you
• The detective hook keeps the whole class on task, including the students who avoid word problems
• Real rigor - students choose the operation from the story, not from a key word
• Builds critical thinking alongside computation fluency
• Answer keys included, so it works for a sub or a parent volunteer

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