VASANT Yeshwant Gharpure of Pune palms a very unlikely calculator -- one made of cardboard, but capable of addition, subtraction and squaring upto four digits, including decimals. "The principles," says Gharpure, "are very simple and follow those of the well-known slide rule and log tables."

The doodad can even handle logarithm tables. Gharpure, who teaches at Pune's Gyaneshwar Degree College, confesses that "students, including those in engineering colleges, find it difficult to use, because they get confused about the placement of the decimal".

"I have applied for a patent," says Gharpure, "so I would request you not to reveal how I made it and also not to take any photographs. I have asked the government to market the calculator cheaply among rural school children who cannot afford electronic calculators, which cost at least Rs 120. I am not interested in making money nor would I like any private entrepreneur to make money out of this."

A civil engineer by training, 64-year-old Gharpure says, "Mathematics frightens most students because of the way it is taught. But the subject fascinates me. I thought I must do something to popularise the queen of all sciences."