Asking a girl that works at mall for number?

so there is this girl who i think is cute she worked at a store i use to go in and we use to have small talk and stuff... well she switched stores at mall after not seeing her work weeks and she was like ooooh heyyyy whats up? well it took me a while to figure her out and after her helping me and stuff she was like ohhh yeah my name is ...... and i introduced myself also, she was like i see u alot and never knew ur name and i always see u come back say hi soon.... well now long story short i want to ask her for her number.... should i do it???? and if sooo how should i approach it she has tattoo's i was gonna talk to her for a bit about them or something then be like oh i g2g but hey put ur # in my phone and ill call or txt u later and we can keep talking.... hows that???