Illustrative Mathematics
Shirt Sale
Everyone loves a good deal, and your mathematician's job is to calculate the original price when given the discount. A different type of problem than the traditional "find the percent change" has your learners working backwards to...
Curated OER
Math Challenges
Students participate in a series of challenging math lessons designed to engage their critical thinking skills. In these real-world problem solving lessons, student solve symmetry and repeated pattern problems, make lists/tables to...
Curated OER
Equations and Inequalities Projects
Students compose equations and inequalities whose solutions are the integers 1-31 and utilize them to number one month of a calendar. They take notes on two ways to work backwards from a solution: by using the number and by setting x...
Curated OER
Choral Counting I
Using a 100s chart or a number line with a pointer, work with your class to count up to 100 by ones and tens. As a part of daily instruction, prompt your kindergartners to chant count from 1 to 30. Move on to 1 to 50, and then from 1 to...
Teach Engineering
About Accuracy and Approximation
How accurate are robots? Groups draw lines by moving robots backwards and forwards by one rotation of the wheels. Using the appropriate formula, they determine the percent error in the length of the lines in relation to the calculated...
Education Development Center
Creating Data Sets from Statistical Measures
Explore the measures of central tendency through a challenging task. Given values for the mean, median, mode, and range, collaborative groups create a set of data that would produce those values. They then critique other answers and...
Curated OER
Bernardo and Sylvia Play a Game
This activity presents a game played by two learners whose solution is an exercise in creating and analyzing with algebraic inequalities.
Teach Engineering
Ramp and Review (for High School)
Rolling for momentum. As part of a study of mechanical energy, momentum, and friction, class members experiment rolling a ball down an incline and having it collide with a cup. Groups take multiple measurements and perform...
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.
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.
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.