Counting Principle Riddle

Assign Use the Counting Principle first, then the sheet with three or more choices. Assign the license plate sheet for a challenge and the riddle as a review.

Solve 12 counting principle problems, like 4 books in a row or 5 runners in a race, to solve a riddle. The directions on the page read: Solve each problem and write the answer on its line. Find the answer in the bank. Write its letter in the riddle box above the problem number. The page opens with a worked example, and an answer key is included.

Yes, both. We made it for 8th grade probability, and it works the same at home or at school. At home, a student can work through it alone and then go over it with you, which shows quickly what is solid and what needs another look. In class it works as independent practice, homework or a warm-up, and you can print one copy or a full set.

Multiply the number of choices for each step. With 6 hats and 7 scarves there are 6 times 7, or 42 outfits.

Each step has one fewer choice than the step before. A 3-digit code from 1 to 9 with no digit twice has 9 times 8 times 7, or 504 codes.

Yes. The number of outcomes at the bottom of a tree equals the product of the choices. The Counting Principle vs Tree Diagram sheet has students check that both answers match.

Yes. Each of the 5 counting principle sheets comes with an answer key.