ThisNrich jigsaw a great way to reinforce children's understanding of the sequences contained within the hundred square even if they have seen it before. It could be used as an exploratory tool for children who haven't met the 0 - 99 hundred square before (puzzles 2 and 4 in the interactivity), or it could play a part in assessing their understanding of it, if they have already met it.

Students explore combinations using colored blocks in this Nrich activity. The activity emphasizes mathematical reasoning and discourse.

This Nrich problem is a good, yet simple, activity that can get pupils thinking hard about numerals, numbers and place value. It also provides a context for discussing different ways of recording and for encouraging systematic working.

This Nrich activity enables pupils to help to develop their concept of fractions and begin to add fractions with the same denominator and denominators that are multiples of the same number. It provides a context within which pupils can explore and reason about properties of fractions.

This Nrich activity enables pupils to help to develop their concept of fractions and begin to subtract fractions with the same denominator and denominators that are multiples of the same number. It provides a context within which pupils can explore and reason about properties of fractions.

In this Nrich article, Alf outlines six activities using the Gattegno chart which begin by developing learners' awareness of reading, writing and ordering numbers, then progress to gaining awareness of multiplication facts, multiplication and division by 10, onto fractions as operations and, finally, to finding percentages of any number.

In this Nrich problem students can work on both prime factorization and area of rectangles.

At the basic level, these Nrich challenges offer chances for children to practice number recognition, one-to-one correspondence and counting. However, some will begin to analyze and compare the three versions, explaining their findings and possibly drawing on ideas associated with probability.

This Nrich problem follows on from Twisting and Turning and More Twisting and Turning and offers students the opportunity to explore sequences of fractions, make generalizations, and prove conjectures. The rope trick in the first problem offers a moment of surprise when the rope becomes untangled, and this prompts curious students to want to explain what is going on. This third problem in the sequence ties up all the loose ends still remaining.

This Nrich problem embeds adding and subtracting fractions into a bigger problem to increase interest.

These Nrich tasks are a great opportunity for learners to use reasoning to decipher mathematical statements. We often make mathematical claims that are only true in certain contexts and it is important for learners to be able to look critically at statements and understand in what situations they apply.

This Nrich problem involves complicated reasoning about fractions that challenges children's understandings of the concepts involved. It is a good example of how fractions relate to multiplication and division.

This Nrich activity is particularly good in a number of mathematical aspects of learning:
Using mathematical ideas and methods to solve "real life" problems
Using and understanding vocabulary and notation related to money
Organizing and using data
Choosing and using appropriate number operations and calculation strategies
Explaining methods and reasoning
Making and investigating general statements

Students explore combinations in this open-ended Nrich task. Students are asked to discuss and document their work pictorially and numerically.

This Nrich problem requires some simple knowledge of fractions and multiples and demands some strategic thinking. It may offer a good opportunity to compare methods between students - there isn't just one route to the solution. Note that there is no need to use algebra in this problem.

This Nrich problem fits in well with counting and skip-counting (counting by twos etc.) and can be solved by physically modeling the biscuits and decorations with whatever objects are convenient. It is a good opportunity for children to choose the way they represent the problem in order to solve it. It may also be appropriate to introduce vocabulary such as "multiple".

This Nrich problem requires a sound understanding of the relationship between part and whole. It could be used as part of a lesson on finding fractions of numbers and quantities.

This Nrich activity challenges students to translate oral directions into actions to build a pattern with blocks.

This Nrich problem gives children the chance to identify and continue number patterns, counting on and back in ones and twos. It is also a good chance for learners to understand the benefits of a trial and improvement approach.

This Geometry Concept Collection is a rigorous presentation of high school geometry. It is fully correlated with the Common Core State Standards.