Could you check these sentence, please?

I don't know how to write n.2

1) 17 students from my I C look forward to corresponding with yours. On Monday I will let you know their class email adress so we can start the email partnership.
2) I measured (took is better?) my son the temperature and I ...... he had 39°C (I don't know how to express it).

When you are beginning a sentence with a number, it needs to be spelled out.

What is 'I C'??

1. Seventeen students from my I C look forward to corresponding with yours. On Monday, I will ...

2. I took my son's temperature, and it was 39°C.
OR
My son had a temperature of 39°C.