Choose any nonnegative number. x 15 (square) Square your number. (x) 2 = x 2 152 = 225 (multiply) Multiply the result by 9. x 2 ∙ 9 = 9x 2 225 9 = 2025 (square root) Take the square root of the result. = 3x = 45 (add) Add 15 to the result. 3x + 15 = 3x + 15 45 + 15 = 60 (divide) Divide the result by 3. = x + 5 60 ÷ 3 = 20 (subtract) Subtract 5. x + 5 – 5 = x 20 – 5 = 15 It’s your original number! x (Yeah!) 15 (Yeah!) Excellent Acceptable Unacceptable Correctness of Trick (10 points) You have correctly shown why your trick works (using variables). Your trick has a few minor errors. Your trick has major errors. Your trick gives the desired result for any number you tell your audience they can choose. (i.e., the domain is correct) Your trick works for only some numbers in your domain (or you didn’t “warn” your audience). Your trick works for only some numbers or no numbers in your domain (or you didn’t “warn” your audience). (8 – 10 points) (4 – 7 points) (0 – 3 points) Complexity of Trick (6 points) Your trick involves several steps that are complicated enough that your audience would be surprised. You have several steps, but they aren’t complicated enough to trick an audience. Your trick involves only a few steps, and they aren’t complicated enough to trick an audience. You used four or more different operations. You used only three different operations. You used two or fewer different operations. Your trick is quite different from the example given. Your trick is somewhat similar to the example given. Your trick is very similar to the example given. (5 – 6 points) (3 – 4 points) (0 – 2 points) Correctness of Example (4 points) Each step of the example is done correctly. There are a few minor errors in your example. There are major errors in your example. (3 – 4 points) (2 points) (0 – 1 point) Don’t steal this one—make yours different! Operation Step General Example
Choose any nonnegative number. x 15 (square) Square your number. (x) 2 = x 2 152 = 225 (multiply) Multiply the result by 9. x 2 ∙ 9 = 9x 2 225 9 = 2025 (square root) Take the square root of the result. = 3x = 45 (add) Add 15 to the result. 3x + 15 = 3x + 15 45 + 15 = 60 (divide) Divide the result by 3. = x + 5 60 ÷ 3 = 20 (subtract) Subtract 5. x + 5 – 5 = x 20 – 5 = 15 It’s your original number! x (Yeah!) 15 (Yeah!) Excellent Acceptable Unacceptable Correctness of Trick (10 points) You have correctly shown why your trick works (using variables). Your trick has a few minor errors. Your trick has major errors. Your trick gives the desired result for any number you tell your audience they can choose. (i.e., the domain is correct) Your trick works for only some numbers in your domain (or you didn’t “warn” your audience). Your trick works for only some numbers or no numbers in your domain (or you didn’t “warn” your audience). (8 – 10 points) (4 – 7 points) (0 – 3 points) Complexity of Trick (6 points) Your trick involves several steps that are complicated enough that your audience would be surprised. You have several steps, but they aren’t complicated enough to trick an audience. Your trick involves only a few steps, and they aren’t complicated enough to trick an audience. You used four or more different operations. You used only three different operations. You used two or fewer different operations. Your trick is quite different from the example given. Your trick is somewhat similar to the example given. Your trick is very similar to the example given. (5 – 6 points) (3 – 4 points) (0 – 2 points) Correctness of Example (4 points) Each step of the example is done correctly. There are a few minor errors in your example. There are major errors in your example. (3 – 4 points) (2 points) (0 – 1 point)