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 shows how to work backwards to find the missing number in a 2-digit addition problem. The video is followed by practice problems to assess student...
CK-12 Foundation
Ck 12: Elem Math: Adding and Subtracting With Parentheses Missing Number
[Free Registration/Login may be required to access all resource tools.] This is a video and practice problems finding the missing number of a multi-step addition and subtraction problem that has parentheses. The video models the process...
Math Is Fun
Math Is Fun: Compound Interest
Explains, with examples, what compound interest is and how to calculate it using a formula. Also shows how to work backwards to calculate the present value of an investment, how compound interest is calculated for different compounding...
Other
Math Stories: Working Backwards
At this one page site you can work through step by step a sample problem that illustrates the problem solving strategy for "Working backwards." The answer is right there to help you check your thinking.
CK-12 Foundation
Ck 12: Elem Math: Subtraction Complete the Subtraction Sentence
[Free Registration/Login may be required to access all resource tools.] The video describes how to work backwards working with 3-digit numbers to determine what number is missing in the subtraction sentence. The video is followed by...
CK-12 Foundation
Ck 12: Elem Math: Mixed Operations Subtraction and Addition I Word Problems
[Free Registration/Login may be required to access all resource tools.] The video describes how to work backwards using addition and subtraction to solve for a specific value.
CK-12 Foundation
Ck 12: Elem Math: Balancing the Equations Numbers to 1000
[Free Registration/Login may be required to access all resource tools.] The video shows how to use addition and subtraction to keep an equation balanced by working backwards to determine the missing value. The video is followed by...
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...
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...
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.