According to the information provided, it is impossible to determine the specific interest rate or calculation method. The following are possible scenarios and calculation examples:

1. If the interest is calculated at the annual rate:

A) Suppose the annual interest rate is r and the monthly interest rate is r/ 12 (assuming 12 months per year).

B) Calculate the interest for three months: 150000× (r/ 12 )× 3.

2. If the interest is calculated at the monthly interest rate:

A) suppose the monthly interest rate is r.

B) Calculate the interest for three months: 1.5 million× r× 3.

Please note that the interest rate can be fixed, floating or other forms according to the actual situation. In addition, there may be other fees or conditions. Therefore, specific interests need to be determined according to relevant contracts or agreements.

Summary:

According to the information provided, it is impossible to accurately calculate the interest of 654.38+0.5 million for three months and four months. The specific interest rate depends on the calculation method of interest rate and other possible circumstances. For accurate calculation, please refer to relevant contracts or consult lending institutions.

Extended data:

-In China, the loan interest rate is usually determined according to the benchmark interest rate of the central bank and the market competition.

-According to relevant laws and regulations in China, lending institutions need to provide contracts or agreements to borrowers, and specify conditions such as interest rates and repayment methods.

-The calculation method of loan interest may be different due to factors such as loan type, loan amount and term.