Purple Math
Purplemath: Finding Quadratics From Their Zeroes
Students often have difficulty "working backwards" from the solution of a problem to its original question. Finding a polynomial, given its roots, is an example of a "working backwards" problem. Here are several examples using different...
University of Cambridge
University of Cambridge: Nrich: Routes 1 and 5
Sharpen your logic and basic arithmetic skills while working on this challenge. Solution.
PBS
Pbs Learning Media: Logical Leaps: Rational Numbers on the Number Line
In this interactive, use logic to solve riddles involving a wallaby jumping contest. Then, place each contestant's jump -- a fraction, mixed number, or decimal between -5 and +5 -- at the correct point on the number line. Backward jumps...
Annenberg Foundation
Annenberg Learner: Patterns in Mathematics: Mystery Operations
This interactive activity allows you to change an equation's numbers in an attempt to figure out what operations are being used to control the answers.
Other
Interactive Algebra: Factoring Helper
This interactive site allows you to enter a quadratic expression and work through the steps of factoring. Hints and the answer are available to help with the process.
PBS
Pbs: Logical Leaps: Rational Numbers on the Number Line
In this interactive, use logic to solve riddles involving a wallaby jumping contest. Then, place each contestant's jump-a fraction, mixed number, or decimal between -5 and +5-at the correct point on the number line. Backward jumps are...
PBS
Pbs: Logical Leaps: Adding Rational Numbers on the Number Line
In this interactive, use logic to solve riddles involving a wallaby jumping contest. Add two consecutive jumps and place them on a number line, finding equivalent fractions and common denominators to do so. Backward jumps represent...