The Boots 425 Scientific was a rebranded version of the Casio FX-31 released in 1981. This scientific calculator measured 85mm x 145mm x 22mm and weighed 134g without batteries. It was powered by two AA batteries or could be used with a 3V DC adapter.
The Boots 425 had a bright blue vacuum fluorescent display (VFD) that showed 8 digits plus a 9th digit for negative numbers. The plastic casing was white on the bottom and black on top with a metallic sticker wrap around the top displaying the Boots brand name. It had a typical rubbery Casio keyboard for entering numbers and functions.
For features, the Boots 425 supported standard math functions like add, subtract, multiply and divide as well as more advanced scientific features. It could do exponents, roots, trigonometry, logarithms and calculus functions. The memory allowed storing a single number. An interesting capability was entering angles in degrees, minutes and seconds using dedicated keys. Results were displayed in decimal form but could be switched to DMS format.
The Boots 425 offered good functionality for a scientific calculator of its time. It did up to 6 levels of parentheses and preserved 10 digit precision internally. However, it lacked some more advanced capabilities like graphing, programmability or equation solving. The small display limited the number of digits visible. Error handling was also basic – overflow or divide by zero just displayed an error code that could not be recovered from.
Overall the Boots 425 Scientific provided a solid set of math and science features in a compact handheld package. It was a rebranded version of a popular Casio calculator of the early 1980s targeted at the student market. While limited compared to modern graphing calculators, the Boots 425 delivered good functionality for a scientific calculator of its era.
