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### Number and algebra

### Geometry and measure

### Probability and statistics

### Working mathematically

### Advanced mathematics

### For younger learners

# Getting Round the City

For ideas on how this problem and others from the Dotty Grids Collections can be used in the classroom, you may be interested to read this article.

A printable version of this problem is available as a Word or Pdf file.

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Age 11 to 16

- Problem
- Student Solutions
- Teachers' Resources

For ideas on how this problem and others from the Dotty Grids Collections can be used in the classroom, you may be interested to read this article.

A printable version of this problem is available as a Word or Pdf file.

Many numbers can be expressed as the difference of two perfect squares. What do you notice about the numbers you CANNOT make?

Take any prime number greater than 3 , square it and subtract one. Working on the building blocks will help you to explain what is special about your results.