I just want an explanation of why it is divided by 4 and how did the $683,035.50 get there. And the F1 number.

Rectangular Arbitrage (3-month): i=2.523%/4 USD $1,000,000 So= 0.90145 Euro 901,450 USD $1,006,307.49 / $683,035.50 F1=0.7585 i=-0.41786%/4 900,508.23 I did a covered interest arbitrage with the USD and the Euro. After performing the arbitrage, I would lose money if I did the arbitrage with the Euro and waited the 3 month. I would lose $323,271.99