Illustration Explanation This is a number puzzle program. A train is standing in a station waiting for passengers to board. The task is displayed on the screen, telling you how many passengers are needed and the number of carriages you have to fill. The displays also shows which numbers can be used to complete the operation. The user clicks the mouse on the appropriate number. This number appears on the carriage door and passengers appear in the carriage windows. A running total of the number of passengers used is displayed on the screen. When the carriages have been successfully filled, a message is displayed, the train whistle is heard and the train pulls out of the station. If the number of passengers selected is too large a warning message is displayed on the screen. There are three levels of difficulty with this program which are characterised by a greater number of carriages, the size of the target number of passengers and the range of numbers you can use to fill the carriages. ‘Easy’ uses two numbers from 1- 5 with a maximum total of 35 and 4- 7 carriages. ‘Moderate’ uses two numbers from 1- 9 and a maximum total of 99 and 7- 11 carriages. ‘Hard’ uses three numbers and a maximum total of 99 and 7- 11 carriages. This is the control bar for the program. The buttons are operated by clicking the mouse on the appropriate button. Clicking on this button will give you an overview of how the program works and the function of each of the buttons. Clicking this button will start a new randomly chosen game at the level displayed. This button should be clicked after each game is successfully completed and a new game is required or when a new level of game is chosen. This button shows the level of the game you are playing. There are three levels of difficulty: Easy; Moderate; Hard. Clicking the up arrow will move you up a level, clicking the down arrow will move you down a level. These buttons show you which numbers you can use to fill the carriages. The program provides the possible numbers you can use and sometimes only two numbers are displayed. This button allows you to undo previous choices of number. Each click undoes one number and can be used repeatedly until all carriages are empty.