The analysis process is as follows:
400 degrees (300-250 degrees) =8 minutes.
300x8-250x8=400
Operation sequence of four operations:
1. If there is only addition and subtraction or only multiplication and division, it is calculated from left to right.
2. If primary operation and secondary operation exist at the same time, the secondary operation is calculated first.
3. If there are primary, secondary and tertiary operations (i.e. power, root and logarithm operations) at the same time, calculate the tertiary operation first, and then calculate the other two levels.
4. If there are brackets, count the numbers in brackets first (no matter what level, count first).
5. The third level should be counted in brackets, and then the second and first levels should be counted.