Answers:
Both your sentences are grammatically incorrect. If your question however is the proper spelling of the word PRACTICE/PRACTISE, then both spellings are correct but it depends on which english standard are you using. The two common and mostly accepted english standards are that of American and British. Practice with a "C" is the american way of spelling the word correctly and Practise with an "S" is the british way of spelling the word. You can choose either to use british and american english, but if you choose to use british, you have to be consistent with your spelling, grammar, syntax etc.
I hope I was able to help you.
cheers.