This interactive Flash puzzle helps children develop number sense and an understanding of our decimal number system. A 0-99 square has been cut into 11 irregular pieces which the user re-assembles. A printable (pdf) version is included along with questions for Getting Started and a Teachers' Resources page with implementation suggestions.

This number challenge is an opportunity to reinforce mental arithmetic and order of operations while developing systematic work habits. Students are asked to use the numbers 4, 6, 6, and 8 (exactly once each) and the four basic operations to find as many ways as they can to represent the number 24. There are over 60 different ways! The Teachers' Notes page includes suggestions for implementation, discussion questions, ideas for support, and a link to a related article, Opening Out. (cataloged separately).

In this open-ended investigation, students use visualizing skill and work systematically to explore surface area. Learners use linking cubes to build three-dimensional objects with exactly 28 faces exposed. Ideas for implementation, extension and support are included.

This problem reinforces the telling of time on a digital clock, and it requires students to work systematically. The number of 'times' the digit 5 appears in a 24-hour period is a matter of a solver's assumptions. Ideas for implementation, extension and support are included along with a printable poster. A link to an interactive Class Clock (cataloged separately) is provided.

This page provides a problem solving resource for teachers to use with their students in the days leading up to Christmas. Twenty-four math problems from the NRICH collection have been included in this advent problem set based on the theme of Planet Earth; each problem includes teacher resources, a printable page, and a solution

This problem introduces repeated doubling in the context of a plant with branches that split into 2 more branches every week. The problem lays the foundation for understanding exponential growth and lends itself to a variety of representations. The Teachers' Notes page offers rationale, suggestions for implementation, discussion questions, and ideas for extension and support.

In this problem learners practice addition, subtraction and multiplication while developing logical reasoning. Solvers apply the given clues along with their understanding of the domino numbering system to determine which dominoes are missing from a set. The Teachers' Notes page includes suggestions for implementation, discussion questions, ideas for extension and support, printable sheets of dominoes (pdf), and a link to an interactive Dominoes Environment (cataloged separately).

This activity reinforces the concepts of area and perimeter and their independent relationship. Students analyze and compose shapes made from unit squares that satisfy area and perimeter specifications. Ideas for implementation, extension and support are included along with printable sheets and shape cards.

This problem builds on simple sorting skills and gives children the opportunity to use logical reasoning. Students describe the characteristics of ten marbles using their different color markings and then design a color scheme for marbles to show specific attributes. The Teachers' Notes page offers rationale, suggestions for implementation, discussion questions, ideas for extension and support.

This collection from NRICH provides activities to help learners think and work like a mathematician. Tasks have students exploring, questioning, working systematically, visualizing, conjecturing, explaining, generalizing and justifying. Activities are organized under specific strategies and processes.

This collection from NRICH provides activities to help learners think and work like a mathematician. Tasks have students exploring, questioning, working systematically, visualizing, conjecturing, explaining, generalizing and justifying. Activities are listed under strategies and processes.

In this creative thinking activity students must determine how many combinations can be made when putting three beads into bags. To complete the activity students must create their own recording system to make sure they are not repeating solutions and they have found all possible solutions. Included in this resource are teacher’s notes with suggestions for introducing the activity, discussion questions, support suggestions, and a printable version.

This problems is an opportunity to explore triangular numbers in the familiar context of decorating a birthday cake with a number of candles corresponding to a child's age. The problem lends itself to systematic strategies and multiple representations. The Teachers' Notes page offers rationale, suggestions for implementation, discussion questions, and ideas for extension and support.

This problem provides an opportunity for students to develop problem solving skills while applying skip-counting and exploring the concepts of multiples and factors within 20. It is posed in the context of toppings on cookies ("biscuits" in the UK) and lends itself to multiple representations. The Teachers' Notes page offers suggestions for implementation, discussion questions, ideas for extension and support, and downloadable handouts.

In this problem students explore the concept of proportion by comparing the relative strengths of different mixes of juice flavor and water in a visual context. Given four mixtures represented by purple and white rectangles, students order the drinks from strongest to weakest flavor and explain their reasoning. The Teachers' Notes page offers suggestions for implementation, discussion questions, and ideas for extension and support.

This problem requires a sound understanding of the fraction relationship between part and whole and can be used for finding fractions of numbers and quantities. Students are given the fractional amount of apples in a fruit bowl and the specific number of other fruit in the bowl in order to figure out how many apples are in the bowl. The Teachers' Notes page includes suggestions for implementation, discussion questions, ideas for extension, a link to a worksheet which provides student support, and a downloadable pdf of the puzzle.

This problem introduces children to algebra by looking for a pattern and generalizing with a rule. Students explore in how many different ways can a stick of 6, 7 or 8 different colored interlocking cubes be broken into two parts. The Teachers' Notes page offers rationale, suggestions for implementation, discussion questions, and an idea for support and extension.

This problem promotes logical thinking and introduces learners to the trial and error (guess and check) problem solving strategy, especially with the interactive provided. In this problem children need to understand the difference between having a certain number of brothers and the number of boys in a family to answer the question, "How many children are there in the Brown family?" The Teachers' Notes page offers suggestions for implementation, discussion questions, ideas for extension and support, and a link to a down loadable worksheet for students to table their trials.

This activity asks students to visualize and construct three-dimensional objects from the two-dimensional drawings. Students are shown four solids composed of cubes, and they must reproduce the objects with manipulatives or sketch them on isometric dot paper. Ideas for implementation, extension and support are included along with a printable sheet of dot paper.

This activity gives students practice naming and using shape and color attributes to create patterned sequences. The first challenge asks students to use attribute differences to extend a sequence. A second, more open-ended challenge asks students to maximize the length of their sequences under a further constraint. An interactive applet is provided as an alternative to physical manipulatives. The Teachers' Notes page includes suggestions for implementation and discussion questions.