Complex sentence: On the same day, new decimal banknotes were introduced to replace the existing pound banknotes, in denominations of $1, $2, $5, $10, $20, and $100.
Split into simpler sentences: On the same day, new decimal banknotes were inroduced to replace the existing pound banknotes. The first dollar banknotes were isuued in denominations of $1, $2, $5, $10, $20, and $100.