CK-12 Foundation
Ck 12: Elem Math: Completing the Addition Sentence Sums to 100
[Free Registration/Login may be required to access all resource tools.] The video describes how to fill in a missing number in an addition problem by working backwards. The video is followed by practice problems to assess student...
University of Cambridge
University of Cambridge: Nrich: Daisy Game
Sharpen your problem solving and strategy skills by playing this interactive game. The game's rules are simple, but play requires some thinking if you want to beat the computer. You can change the settings and see if your strategy works...
University of Cambridge
University of Cambridge: Nrich: Two Stones Game
Sharpen your problem-solving and strategy skills while playing the interactive game, Two Stones. The rules are simple, but the game requires some thinking if you want to beat the computer. Watch as the play proceeds to see what it takes...
E-learning for Kids
E Learning for Kids: Math: Riksjas, Toek Toek: Subtraction
Learn how subtraction works with Som the Tuk Tuk driver.
CK-12 Foundation
Ck 12: Elem Math: Adding and Subtracting Missing Operation
[Free Registration/Login may be required to access all resource tools.] This resource includes a video that demonstrates how to find a missing operation in a multi-operational addition and subtraction problem. Practice problems follow...
University of Cambridge
University of Cambridge: Nrich: Game Counter Roundup
Sharpen your problem solving and strategy skills playing this interactive game, Counter Roundup. The rules are simple but the game requires some thinking if you want to beat the computer. There is a "Get Printable Page," link at the top...
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...