The Decimo Vatman was a Japanese made calculator for the British market, this one probably made in about 1974 or 1975. The name Vatman refers to Value Added Tax which was introduced into Britain in 1973. The introduction of the new tax caused many headaches for businesses it is said, so no doubt the Vatman with it's VAT key helped!
This key is just a percentage function, and the figure needed to be multipled by 8 for the then-VAT rate of 8% (sadly it is a lot higher now!) The calculator has an eight digit green fluorescent display. As well as the basic four functions and percentages (VAT) it also has square root, square and power functions.
Unfortunately, my example no longer seems to work. The battery compartment has some corrosion.
