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

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 lesson is to teach the problem-solving strategy using the CUBES acronym. The students will use digital photos to create real-life story problems of their own and practice using the CUBES strategy to solve the problems they create as well as those of their peers.

In this article the author suggests three ways teachers can support learners to become confident and competent problem solvers. Each suggestion is discussed in detail with links to NRICH tasks and articles to provide further understanding of this complex process. The article can also be downloaded as a PDF.

This 13-page article presents eight aspects to consider when creating a classroom culture that supports problem solving. The article identifies each of the eight aspects and then goes into more detail suggesting activities that can be done in the classroom to promote more student discourse and problem solving. Throughout the article are links to supportive math activities, research articles and professional development activities.

This interactive Flash applet provides a customizable set of dominoes that users can manipulate to play games or solve puzzles. It can be used with an interactive whiteboard to facilitate group work. Users can determine the size of a set (up to double-9), remove individual dominoes, rotate and move them, and change their size. The Teachers' Notes page includes a link to page containing domino games and challenges (cataloged separately).

In this problem students study motion along a path and the properties of a parallelogram. Students must navigate back to a starting point after traveling three legs in cardinal directions on a compass. Ideas for implementation, extension and support are included.

This article highlights a number of mathematical strategy games that are available on the NRICH website. Most have interactive versions but also can be played offline. The author explains their value in the classroom, offers suggestions for implementation and extension, and provides links to the games and to other related articles.

This brief article describes Samuel Morse and the code first used by telegraph operators in the 19th century. The time intervals used in transmissions are detailed, and there is a connection between the code and letter frequencies in the English alphabet. Included is a link to a printable page and a Morse Code font for Windows.

This problem requires children to make sense of information and to work in a systematic way. The interactive is a machine with four colored lights, each corresponding to a rule regarding number properties. Students are to discover numbers that will satisfy all four rules and switch on all the lights. The Teachers' Notes page offers rationale, suggestions for implementation, discussion questions, ideas for extension and support.

This lesson plan created by Tanner Dance at the University of Utah includes a video and plan for teaching dance, math, and money. The plan includes a springboard book, a warm up, and various dance/math integration activities.

This web page provides instructions for a basic form of Nim, an ancient game that develops strategic thinking. Starting with a total of 7 counters, two players take turns removing one or two at a time. The player who takes the last counter wins. The game of Nim is very adaptable. This page includes questions that encourage players to generalize a winning strategy as well as a link to another page describing several of variations.

In this problem learners explore square numbers and the relationships between them while practicing basic number skills. By applying a systematic strategy they determine three numbers that satisfy the conditions of the scenario. There are links to hints and a solution page; Teachers' Resources include suggestions for implementation, reflection, and differentiation.

In this problem students apply basic proportional reasoning in the context of a pie recipe. Given a recipe for 80 pies, Peter needs to determine whether the ingredients he has on hand are enough to make 2 pies. The Teachers' Notes page offers rationale, suggestions for implementation, discussion questions, ideas for extension, and printable lists of ingredients (doc).

This problem gives children an opportunity to explore patterns in a practical context and to generalize the results with a rule. Students investigate how many blocks would be needed to build an up-and-down staircase with any number of steps up. An interactivity in the hints shows the blocks transformed into a square pattern. The Teachers' Notes page offers suggestions for implementation, key discussion questions, ideas for extension and support.

This interactive problem provides an opportunity for children to become familiar with Venn diagrams, while reinforcing knowledge of number properties. Students must place the numbers from 1 to 40 into a Venn diagram of two sets with an intersection. The Teachers' Notes page offers rationale, suggestions for implementation, discussion questions, ideas for extension and support.