Copyright © University of Cambridge. All rights reserved.

$4,000,000$

$$2000+1999\times2000=(1+1999) \times 2000= 2000 \times 2000=4000000 $$

$$2000+1999\times2000=(1+1999) \times 2000= 2000 \times 2000=4000000 $$

*This problem is taken from the UKMT Mathematical Challenges.*