10 full days, starting the day after contact?

[Enddateconfusion]

I’m pretty sure the isolation dates given by my DCs school don’t quite add up but I wanted to check.

Last contact with positive person: 7th July.
The end date given (inclusive): 18th July.

Am I wrong in thinking they’ve got DC isolating for 11 days and not 10? 10 full days, starting the day after contact, Takes us to the 17th. Would it be wrong of me to take dc out for a long walk and much needed scenery change on that 11th day?

Ends end of 17th. OK to go out 18th

Thank you!

If you are sure it was the 7th then yes you are right. I don't think they can count, and have said day 1 is 8th (as 7th was day 0) and therefore ten days is 18th when it isn't. Tbh I'm not convinced dds school haven't done the same. Kid last seen 7th, isolation till 18th. But it's secondary school so can't be sure which kid it was.

I thought the same when DS was told to isolate by school. Queried it and they said the end date in the letter was the date they can go out/return to school (eg isolate until Saturday 17th means stay at home until 23.59 on Friday 16th).