Problem-solving Investigations - Year 4
Website The problems below are designed to help children identify patterns, explore lines of thinking and investigate properties of numbers, shapes and measures.
Problem-solving Investigations - Year 3
Website The problems here are designed to help children identify patterns, explore lines of thinking and investigate properties of numbers, shapes and measures.
Thinking of a Number- Top Marks
Interactive Guess the number by revealing the clues on the clouds one by one. This site lends itself to use on an interactive whiteboard.
Bobbie Bear's outfits
Interactive Bobbie Bear is planning a vacation and wants to know how many outfits can be made using different colored shirts and pants.
Puzzles- Maths Zone
Website Great selection of interactive puzzles and problems solving from Maths Zone.
Puzzleboxx
Website PUZZLEBOXX is a collection of puzzles and problems suitable for children (aged 9 & upwards) and adults.  Some are fairly simple.  Others may take some time.  Some require pencil and paper.  Others may require a practical solution.  Almost all of them will be easier to solve if you discuss your ideas with a partner.
Working systematically- nRich
Website

Finding All Possibilities Upper Primary

These activities focus on finding all possible solutions so working in a systematic way will ensure none are left out.
Free problem solving- Maths Sphere
Website A great set of maths puzzles for upper primary children. All answers are given. Many teachers use these as a weekly challenge. They are ideal for printing out in colour and laminating, making a long lasting resource. These puzzles can also be found in MathSphere: It's All Figured Out!
Year 3 and 4 problem solving-TES
Resource Excellent problem solving pack with problems for Years 3 and 4. There are a number of correspondence problems in this pack.
Correspondence-Primary Resources
Website A number of correspondence problems on the Primary Resources site: See Clothing Combinations, T Shirt combinations, Houses and Flowers,  
Gary Hall- Read , write and order numbers to 10,000,000
Website  A selection of worksheet resources which can be copies into an IWB.