A Computer Arithmetic developer is responsible for designing, implementing, and testing algorithms for arithmetic operations in computer systems. They focus on improving the accuracy, speed, and efficiency of computations. This involves developing algorithms for basic operations such as addition, subtraction, multiplication, and division, as well as more complex computations like square roots, logarithms, and trigonometric functions. They also work on handling exceptions, such as division by zero or overflow. Their work is crucial in fields that require high precision calculations, including scientific computing, cryptography, and machine learning.