What is the sum of 2 and 4?

E Fluid Technology Co., Ltd.
Unit 104, Building 6, No.650 Shunqing Lu, Shanghai
Postal code: 201612
Phone +86 (0) 21 / 6477 9206

Guangzhou office
Unit 1314, Building 6, Aoyuan City Plaza, Guangzhou
Postal code: 511400
Phone +86 (0) 20 / 3739 2701