The four games in Number Puzzler are an exciting way of improving your ability to do mental arithmetic. Starting with easy one digit sums like 7 + 2, right up to monsters like 47 + 35, you play against the computer or a human friend if one is around. The winner is the one who plans his moves more carefully.

Three of the games involve a sort of combined bingo and numerical noughts and crosses, where you can decide whether you want to do either addition or subtraction or both at the same time. You can also decide whether to play with numbers just up to 9 or up to 99. The fourth game involves building magic squares.

Test yourself. Once of the options in Number Puzzler is a self test. You can use it to see how you're improving.

The program starts by asking you to choose which of five different games you want to play.

Addition, Subtraction and Adds And Subs are all games based on numerical noughts and crosses.

In Magic Square you have to complete a board a numbers by selecting more numbers to make a certain total.

In Self Test you can set yourself a test in addition, subtraction or both.

Select the game you'd like to play and then read on:

For each of these games you must now decide who is going to play and which board size you would like to play with.

If there is only one player, he or she plays against the computer (called "Dragon" on the screen).

The board, made up of squares, can be 3*3 or 6*6. On a 3*3 board, the numbers you play with range between 1 and 9. On the 6*6 board the numbers go up to 99 and the game really involves playing four separate 3*3 boards at the same time.

Having decided all that, you are now ready to start and your board appears on the screen.

The Aim: In each game you have to get three numbers in a line to win. The first player to win five games is the overall winner and the game score is shown opposite the players' names.

Addition. Press the Space Bar to start. In the two boxes, on the left below the board two numbers appear. You can either use these two numbers as they stand or the sum of the two numbers. For example, if 5 and 2 appear bottom left, the player can either enter the two numbers - 5 and 2 in the boxes on the right hand side, or the one number - 7.

Subtraction. Press the Space Bar to start. One number appears below the board on the left. The number can be split and the two numbers chosen, or the original number itself, put on the board. Thus, 7 could be split into 5 and 2, or 4 and 3, or 6 and 1.

Adds And Subs. Press the Space Bar to start. Two numbers appear below the board on the left. In this game, both numbers can be used as they are, or added together (as in Addition), or *either* number can be split up (as in Subtraction).

There are two boxes below the board on the right hand side. The colour of these boxes shows whose turn it is. If Player 1's name is in blue and the boxes are blue, it is that player's turn. If the boxes are green, it is player 2's turn.

Select your first number, type it into the first box and press ENTER. If you are selecting another number, type it into the next box and press ENTER. These numbers are then entered on the board and it is then the other player's turn after the Space Bar is pressed.

If your addition or subtraction is incorrect, the ? sign appears. Press the Space Bar and you have one more chance to get it right, after which you lose your turn.

If you try and make a number already owned by the other player, the ? sign appears and you lose your turn when you press the Space Bar (you can, however, select a number that you already own).

You first have to choose a number between 3 and 20. A 3*3 board then appears on the display with certain numbers in it.

The aim is to fill all the other squares so that the total of each column, row and diagonal is the same - or as many as possible are the same.

Points are awarded for this; you must try and get 100 points in three turns.

At any time you can press the S key and the computer will show you a solution (but you won't get any points for it!).

Use the Arrow keys on the keyboard to move the flashing cursor to the box you want to fill. Type in the number and press ENTER. Continue to do this until all the boxes are full.

Your score is shown on the screen.

Type in the answer to the various questions you are asked and then, when you are ready to start, press the Space Bar.

Many of our programs incorporate sound. Make sure the volume control on your TV is turned up sufficiently if you wish to hear it.

CLOADM (ENTER)

The programs will begin automatically after loading.