The Mental Arithmetic Calculator is a "mental arithmetic trainer" designed specifically for classrooms and families. Teachers can set addition, subtraction, multiplication, and division, number ranges, and time limits with just one click. Students can provide real-time voice or screen feedback after oral calculation, adding seconds to correct answers and analyzing incorrect answers, forming a personal growth curve. In teaching, it can assist classroom interaction, such as timed competitions; Assist in post class consolidation and targeted improvement; Personalized training can also be provided to suit different students. It can enhance computational proficiency, cultivate mathematical thinking and concentration, and is a good helper for mathematics teaching in various stages.