This series of programs by Chris O' Donoghue is designed for use by children in the lower years of secondary schools or in upper junior schools (9-12), or by parents and children at home. They will also have uses outside these recommended age ranges depending on the ability of the children.

Many children at this age are content to complete a mathematics problem and have it judged 'right' or 'wrong', without any regard for the principles behind it. Many so-called educational programs perpetuate this 'drill and practice' approach, and teachers have rightly criticised this use of computers. We believe that our programs illustrate in an interesting and entertaining way, many of the principles of mathematics at this level. They use animations and simple games - but not frivolous gimmicks. They have been written by a professional teacher, and thoroughly tested in schools. The programs do not attempt to replace the teacher or text-book, but they allow the computer to enrich many maths lessons. At home, they can be used by parents to help with word children are doing at school - or just for fun!

These programs show a simple sequence of ideas: how you locate a point on a flat surface, how you can string some of these points together to form a line, a how a line divides a surface into regions.

PLOTTING is a simple introduction to co-ordinates - the two numbers which locate a point on a grid. When written, these two numbers should be separated by a comma and enclosed in brackets - for example (3,4). Here the computer prints comma and brackets for you. You are given the choice of learning or testing. To learn, enter the two co-ordinates and the point will be shown on the grid. To test, you are shown a point and must enter its co-ordinates. Each round has ten questions.

OVERHILL is a simple variation on BATTLESHIPS in wihch you guess the co-ordinates of an enemy tank correcting your guess until you score a hit. The game is included to develop a feel for co-ordinates.

BOXES is a scaled down version of the familiar game, but using co-ordinates to plot the lines which make the boxes. The computer obligingly puts your letter into a box if you complete one.

LINES takes the connection between co-ordinates and lines a little further than BOXES. Use level 1 of the program first since this shows its use most clearly. If a line has equation X=4, enter it that way rather than 4=X which the computer will regard as wrong; although it is not wrong, X=4 is the more usual way of writing the answer, and it is best to learn the usual convention.

REGIONS has been included to show you that a line defines regions on a surface. The line with equation X=4 consists of all points on a grid with X co-ordinate 4; the region X>4 is that part of the grid where the X co-ordinates are greater than 4. This program therefore introduces inequalities! Again, be conventional and enter X>4 rather than 4>X.