"Dear School: Please excuse John from being absent on Jan. 28, 29, 30, 31, 32, and also 33."
I remember using a similar excuse in my final year of secondary school.
The dates were of course a bit more spread out and didn't contain imaginary dates, but still numbered just as many.
It was like "Please excuse 'Dallinor' the 15th, 18th, 23rd and the 28th of March and the 1st, 3rd, 8th and 12th of April"
They bought it.











