I went to a supermarket to buy some food with my two kidswith my two kids to go grocery shopping. I went to a supermarket with my two kids to go grocery shopping.

This sentence wasn't wrong, but it's more common to say you're "going grocery shopping", rather than "to buy food".

However, the cashier's face expressed kindness, and in particular, she gave me 10 oneten bags while people could originally buy 5five. However, the cashier's face expressed kindness, and in particular, she gave me ten bags while people could originally buy five.

I've definitively been corrected for using Arabic numbers in writing on school assignments. This blog post summarizes some of the academic/ journalistic style guides: https://www.tckpublishing.com/when-to-write-out-numbers/

She said, "Because of your kids, I'll give you more." She said, "Because of your kids, I'll give you more."

I asked the cashier how many plastic bags I could buy, because there is a limit on how many bags people can purchase at once for each market. I asked the cashier how many plastic bags I could buy, because there is a limit on how many bags people can purchase at once.