Greetings of the day!
Let's discuss about mathematics. Calculation & measurements are an important part of it. Hundreds of years ago it's used to measure the distance in old forms. Units to measure the distance were different one like 'Yojana', 'dhanush', 'danda' etc.
1 Yojana = 14.6 km approximately
These type of units were used in ancient time. Like Ramayan, Mahabharata. Some basic concepts of mathematics are in ancient books.
Then in modern time it forms in modern mathematics. It includes hundreds of theorem, equations, series & much more. It's also being used in management, prediction, arrangements, etc.