Math Detectives Activity: Alien Invaders!

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Language Arts, Reading, Reading Comprehension, Mathematics, Operations (+, -, x, /, etc.), Problem Solving

Grade 1- 3


Students become "math detectives" and solve a series of story problems or word problems in order to finish an adventure. The activity connects math and reading while reinforcing critical thinking and problem-solving skills


What is a Problem-Solving Math Mystery?
Children love a good adventure story. It is even more exciting if they are "living" and experiencing the story!The adventure is divided into several parts. Every part has an accompanying math problem that must be solved before the student can move on to the next part of the adventure. Five answers with five page numbers are given with every problem. If the student chooses the correct answer, a page number is given that continues the adventure. If the incorrect answer is chosen, a page number is given that describes a less desirable turn of events, such as being made to do a thousand pushups by an alien fitness instructor. Then the student must return to the last problem and try again.

Work must always be shown to ensure that the child can work and understand the math problem. (Note: If students need more work space they can use the blank page that precedes the page to which they must return.) When the adventure is successfully completed, the student is given an Official Expert Math Detective Badge and promoted to the next detective level.
It is recommended that the teacher have the students work in teacher-selected groups of four that each contain a strong reader and a strong math student (or a child with good problem-solving skills) for optimum success. The students should each have their own story book (detective's notebook) and should each be responsible for showing their work. Remind them that they will have the assistance of other group members to figure out what is being asked and how to solve the problems. It is also beneficial to assign jobs to each group member such as the following:

  1. Reader (This student reads the story parts to the group.)
  2. Recorder (This student can record notes/ideas for group on scratch paper until the final answer is found. Then all members record the work in their individual books.)
  3. Task Master (This student makes sure that everyone is participating and on task.)
  4. Questioner (This student is the only one allowed to raise his or her hand for adult help and then only if no one in the group can answer the question.)
How to Use the Book

Assembling the Story
The book is 24 half-pages long (12 full pages). Once a book is photocopied, it can easily be cut along the dashed lines, collated, and stapled. Each book has illustrated pages, and each of the pages is numbered. It is recommended that three staples be used on the left-hand margin because the pages will be turned often since the problems are scattered throughout the book, not in chronological order. (That would be too easy!)

Reading the Stories and Solving the Math Mysteries
Before students begin, model how to use the book by following these steps:
  • Set the scene for the stories.

  • Explain that the student is a junior math detective on his or her first case. The student detective will be embarking on a special adventure. They will have a detective's notebook (the assembled story book) that tells their story and must be used to show all of their detective's work. (This is best done on the blank back of the page opposite the problem.) If they can solve each problem in the story successfully, they move on to the next part of the adventure and ultimately solve the case, get promoted, and get assigned a new mission. If they cannot solve a problem, something unfortunate will happen to them and they will have to try the problem again!
  • Model how to show the work in the detective's notebook (the storybook).

  • An answer alone is not sufficient. To demonstrate understanding of the problem and its solution, the student must draw a picture, write an equation, or write a simple sentence such as "I got the answer by using the clock model in my detectives kit." Remind students that they must show proof that they know how to solve the problem just like real detectives do when they file a report.
  • Work the first two or three problems with the students.

  • If students have not been exposed to many story or word problems before, this becomes a teachable moment. For a whole class lesson, make an overhead transparency of the problems.

Here are several clues to share with the class. You may wish to post them in the classroom as reminders for students.

Detective Clues for Solving Math Story Problems
  • Every problem should be carefully read two times before trying to solve it.
  • Look for words that give you hints on what is to be done such as "all together" or "in all" which tends to mean you add, and "got away" or "loses" which tends to imply subtraction, etc.
  • Use the detective's kit whenever possible.
  • Read all of the answers before choosing one. At least one or two should obviously be wrong. There are also a few problems with more than one correct answer or an "all of the above" option.
  • If you are really stuck, try working backwards. Choose an answer that looks reasonable and try to prove it correct. (Remind the student, however, that a picture, an equation, or a sentence showing how the correct answer was arrived at must accompany all answers.)
  • Use a bookmark or self-sticking note to mark the page you are on so that you do not lose your place if you turn to a page that is not the correct answer and you have to go back and work the problem again. Remove the bookmark only when your work is shown and you have definitely found the correct answer and the next part of the adventure. Then place the bookmark on this new page and continue as above.
  • When you have found all the correct answers, highlight them on each correct page. Then, read the story from beginning to end using only the correct pages.

Good luck on your adventure!


  • pencils
  • scissors
  • stapler

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