YOU SAID:

i ate two slices of pizza because i wasn't hungry

INTO JAPANESE

お腹が空いていないのでピザを2枚食べました

BACK INTO ENGLISH

I wasn't hungry so I ate two pizzas

INTO JAPANESE

お腹が空いていないのでピザを2つ食べました

BACK INTO ENGLISH

I wasn't hungry so I ate two pizzas