Can you please check these sentences for me?

Question

1)This afternoon my child went bobsleighing with his best friend. They had fun sleiding down the snow.
2)They tumbled (fell headlong) several times. They also went on a sort of plastic pan (with a long handle) whose name I don't know in English.
3)At the end of the day they were soaked
(wet through)but extremely happy.(Can you say: their clothes were dripping wet?)
4)Unfortunaltely, I had to buy my child 5) They also gave him a medal because he participated in a weekly ski course.
6) The ski pistes are all quite easy and this is why a lot of families with children spend their holidays here (come here on their skiing holidays?).
7) My son's primary school teacher has given him (can you use "has assigned"?) him a lot of homework. I believe we'll spend whole next week doing it.
8) On our way back to the hotel we stopped at a clothes shop (offering January sales) in the main street and I bought my son a sleeveless cardigan and a polo-neck shirt.
9)We were given (granted?) a 30% discount on each item.I bought them at a 30% discount. I got a 30% discount (reduction) on each of them???
(Can you say: "the shopkeeper knock off 30% for us"?)

Answer 1

1. sleiding = sledding
3. At the end of the day,... yes
4. I had to buy my child? or do you need to mention what you bought?
6. pistes = trails?
7. we'll spend the whole next week yes.
8. rather than "in" = on the main street
9. th shopkeeper knocked off...

Sra

Answer 2

In #4, what does that mean: "I had to buy my child." -- ??? Doesn't make sense to me.