Any one understands argument in Reading 61 - 7.2.2?

I fairly understood the optional segment 7.2.1, Pricing T-bill Futures, in Reading 61. However, failed to understand the argument in segment 7.2.2, Pricing Eurodollar Futures. Any clues?

me 2, its one of the few things i do not understand, i just skipped it for now… i hope someone can provide an example with numbers and such… i am not getting what they are trying to say