1. The Defendant (Counterclaim Plaintiff) paid KRW 25,613,400 to the Plaintiff (Counterclaim Defendant) and its related amount from August 18, 2017 to October 24, 2019.

1. Basic facts

A. The Plaintiff (mutual name: C) is an individual entrepreneur who runs construction machinery rental business, etc., and the Defendant is a company that aims at reinforced concrete construction business, etc.

B. From December 1, 2016 to March 31, 2017, the Defendant awarded to the Plaintiff the contract amount of KRW 7,184,00, and KRW 28,665,00 for the “F Corporation” (hereinafter “F Corporation 2”) in the D Construction Site (hereinafter “instant First Project”) respectively to the Plaintiff at KRW 7,184,00, and KRW 28,665,00.

(hereinafter referred to as "the first, second construction contract of this case" in sequence c.

On January 10, 2017, the Defendant paid each of the construction cost of KRW 40,77 million to the Plaintiff (including value-added tax) and KRW 51,70,000 (including value-added tax) on February 10, 2017.

[Ground of recognition] Facts without dispute, Gap evidence 1 to 4, Eul evidence 1 to 2 (including each number; hereinafter the same shall apply) and the purport of the whole pleadings

2. Summary of the parties’ assertion

A. Plaintiff 1) Under the instant construction contract, the contract amount under the instant construction contract is an amount that does not include value-added tax. The Defendant paid a total of KRW 84 million to the Plaintiff when excluding value-added tax. As such, the Defendant paid KRW 21,849,000 for the remainder of the construction project (= KRW 28,65,000 for the construction cost - KRW 28,665,000 for the value-added tax - KRW 2,184,90 for the value-added tax - KRW 24,03,90 for the construction cost of the instant construction project) and KRW 24,03,90 for the total of KRW 2,184,90 for the construction cost of the instant construction project. (2) Of the instant first construction project, the construction cost was set at KRW 12,00 for the volume of December 646 meters with earth and sand as a unit price for the construction work price of KRW 230,000 for the construction cost.

Therefore, the defendant should pay the additional construction cost of 7,106,00 won (=646m x unit price 11,000 won).

3) With respect to the instant First Corporation, the Plaintiff supplied each of the Defendant with the H-300 x 300 x 10) 15 and H beamline (H-300 x 200 x 9) 14 with respect to the instant Second Corporation, the H-300 x 300 x 10 x 15 , respectively.