Add & Subtract Fractions with Unlike Denominators

Inside the case file

Adding and subtracting fractions with unlike denominators, mixed numbers included, is the skill your 5th grade class practices in these ten CSI Mini Mystery Detective math cases with a dinosaur dig theme. Six cases are computation and four are fraction word problems. Use them as a math center, for homework or as a morning task. There's no prep, and each case has its own answer key.

Strange things keep happening at Dinosaur Dig Camp, and your students are the fossil detectives called in to find out who's behind them. Each mixed number problem they solve rules out one more suspect, and a page of adding and subtracting fractions with unlike denominators becomes a case they want to close. When just one name is left, they know every answer is right, and that last suspect is the villain.

What's Inside

• 10 one-page dinosaur dig cases with 156 problems in all
• Cases 1 to 6 have 16 fraction and mixed number problems each
• Cases 7 to 10 have 15 short word problems each, about digging, fossils and the camp crew
• An answer key for every case
• Denominators of 2, 3, 4, 5, 6, 8, 10 and 12. Every answer is in simplest form
• A Mixed Numbers Guide that works one addition and one subtraction step by step
• Teacher instructions, a contents page, a Detective's Case Log and a Master Fossil Detective certificate
• 30 pages in black and white, easy to print

The Cases

1. The Stolen T. Rex Tooth - a giant tooth gone from the fossil tent
2. The Missing Dinosaur Egg - a rare egg taken from its sand box overnight
3. The Fake Footprints - fake dinosaur tracks pressed into the mud
4. The Swapped Skull - a real skull switched for a plaster copy
5. The Spiky Tail Tangle - Stegosaurus tail bones mixed up with a back plate
6. The Triceratops Horn Heist - a horn carried out of the dig pit at lunch
7. The Pterodactyl Prank - a paper Pterodactyl hung over the camp
8. The Long Neck Mix-Up - neck bones laid out in the wrong order
9. The Empty Display Case - the best fossil missing from the camp museum
10. The Twisted Trail Signs - trail signs turned around, and the jeep got lost

When to Use This Resource

Start with cases 1 to 6 once your students can find a common denominator. Cases 7 to 10 use the same skills in word problems, so they work well after that. Students who want the steps beside them can keep the Mixed Numbers Guide in their folder. A single case makes a good bell ringer, small group task or sub day page. The pack also suits test prep, intervention and homeschool lessons.

Grade Levels

Written for 5th grade. It covers 5.NF.A.1, adding and subtracting fractions and mixed numbers with unlike denominators, and 5.NF.A.2, the word problems that go with it. 6th grade teachers can use it as fraction review.

Why Teachers Love Mystery Detectives

Every Mystery Detective pack follows the same routine. Students solve, match each answer to a suspect, cross the suspect off and name the villain. After one case they know what to do, even in a new pack. The cases don't depend on each other, so you can hand out one at a time or pick the ones you need. Checking a finished page against the key takes very little time.

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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