1. Casio: Casio's calculator has always been a very cost-effective choice, with stable and reliable product quality, complete functions and moderate price.

2. TexasInstruments: The calculators of Texas Instruments are very popular in the fields of engineering and science, and their products have the characteristics of high precision, high reliability and easy use.

3. Hewlett-Packard (HP): HP's calculator product line is relatively comprehensive, including basic, scientific and graphic, and the price is relatively close to the people.

4. Konka: Konka's calculator is competitive in the domestic market, with affordable products, complete functions and good quality.

5. Philips: Philips calculator is popular in the field of education, and its product operation is simple, which is suitable for students.