Original Text
On that day the day is equalized with the night, [and becomes of equal length], and the night amounts to nine parts and the day to nine parts.
Simple English
On that day, the day and night become equal in length. Each has nine parts.
On that day the day is equalized with the night, [and becomes of equal length], and the night amounts to nine parts and the day to nine parts.
On that day, the day and night become equal in length. Each has nine parts.