You don't need much math foundation to learn budget. You can add, subtract, multiply and divide, and then you can understand the calculation methods of various shapes and areas. Basically, you use middle school mathematics knowledge.
If you want to learn budget, you can do it at any time.
Of course, if you want to learn how to make a budget quickly, you'd better have a foundation in construction technology. A budget officer who knows nothing about construction is not a good budget officer, and a budget officer who knows nothing about construction is likely to miss items, which is a great shame for a budget officer.
Study hard, first look at the picture, then understand the calculation rules, then set the quota, then grasp the policy, then charge, and finally adjust the price to adapt to the market.