{"product_id":"subtraction-within-100-csi-mystery","title":"Subtraction Within 100 CSI Mystery Worksheets | Grades 2–6 | Number 45","description":"\u003cp\u003eMarch math review for 3rd grade, 4th grade and 5th grade on divisibility rules and the multiples of 3 and 9: CSI Mystery Detective worksheets that turn a hundreds chart into a crime scene where the suspect is a number under 100. The class runs a proper investigation, evidence to forensics to line-up to interrogation, and every stage takes more numbers off the board. The clue they keep for good: digits that add to 9 mean a multiple of 9. Nothing to cut, only pages to print. Students decode a cipher, shade the multiples, apply the digit-sum rule and finish on a color-the-clues puzzle that closes the mystery.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eThe Case: The Suspect Number\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cp\u003eAll that is known at the start is that the number is under 100, which is not much to go on. Your students run it as a real investigation - evidence, forensics, line-up, interrogation - and every stage takes more numbers off the board. The clue that does most of the work is the one your class will keep for good: add the digits, and if they come to 9, you have a multiple of 9.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eWhat's Inside\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cul\u003e\n  \u003cli\u003eA letter-and-number cipher that decodes the opening message\u003c\/li\u003e\n  \u003cli\u003eShading the multiples of 3 and 9 on a hundreds chart\u003c\/li\u003e\n  \u003cli\u003eWorking out that every multiple of 9 is also a multiple of 3\u003c\/li\u003e\n  \u003cli\u003eUsing the digit-sum rule to narrow the suspect list further\u003c\/li\u003e\n  \u003cli\u003eA final color-the-clues puzzle that separates the last two suspects\u003c\/li\u003e\n  \u003cli\u003eFull color and black-and-white versions of every page\u003c\/li\u003e\n  \u003cli\u003eAnswer keys for the whole case\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003e\u003cstrong\u003eWhat Is a CSI Mystery Detective Case?\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cp\u003eTake a math escape room, take away the locks and the app, and put a line-up where they were: that is a CSI Mystery Detective case. Students solve, each right answer clears one candidate, and the last standing closes the case. Nothing is cut, prepared or installed. A practice page lets a class drift; detective activities do not, because one wrong answer leaves more than one possibility standing. It works as a full math activity, in math centers, or as math worksheets to hand a substitute.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eWhen to Use This Resource\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cul\u003e\n  \u003cli\u003eIntroducing or consolidating multiples and divisibility rules\u003c\/li\u003e\n  \u003cli\u003eHundreds chart work with a purpose behind it\u003c\/li\u003e\n  \u003cli\u003eMath centers, early finishers and independent work\u003c\/li\u003e\n  \u003cli\u003eEmergency sub plans that run themselves\u003c\/li\u003e\n  \u003cli\u003eBack-to-school weeks and end of year review\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003e\u003cstrong\u003eGrade Levels\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cp\u003eBuilt for 3rd grade, 4th grade and 5th grade. Third graders usually need the digit-sum rule demonstrated once; fourth and fifth graders work it out for themselves and run the rest independently. It also suits 6th grade students who never properly learned the divisibility rules.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eWhy Teachers Love CSI Mystery Detective Cases\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cul\u003e\n  \u003cli\u003eZero prep - print and hand out\u003c\/li\u003e\n  \u003cli\u003eSelf-checking by design, because an early error shows up later\u003c\/li\u003e\n  \u003cli\u003eA divisibility rule students remember afterward\u003c\/li\u003e\n  \u003cli\u003eWorks as a whole lesson, a center, or a filler for an awkward afternoon\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eLove this resource?\u003c\/p\u003e\n\n\u003cp\u003eFollow Kiwiland Education for new detective cases, seasonal math activities and updates on discounts and new releases.\u003c\/p\u003e\n\n\u003cp\u003e\u003ca href=\"https:\/\/www.teacherspayteachers.com\/Sellers-Im-Following\/Add\/Kiwiland\"\u003ehttps:\/\/www.teacherspayteachers.com\/Sellers-Im-Following\/Add\/Kiwiland\u003c\/a\u003e\u003c\/p\u003e","brand":"Kiwiland Education","offers":[{"title":"Default Title","offer_id":62593171685746,"sku":"3501908","price":4.0,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0909\/2848\/0626\/files\/2-digit-sums-and-codebreaking-csi-mystery-printable-worksheets.jpg?v=1792612947","url":"https:\/\/kiwilandeducation.com\/products\/subtraction-within-100-csi-mystery","provider":"Kiwiland Education","version":"1.0","type":"link"}