My kids really enjoy looking at math posters on the wall, working through math games online, and fun math reading like Bedtime Math. Board games are brilliant for strategic thinking, and there are lots of games that require logic/spacial skills, like Rush Hour.
At my kids' school, real math differentiation didn't start until age 6; at age 5, there was so much playtime my oldest didn't mind spending a few minutes doing simple math. Keep an ear on what she thinks about math at school and keep doing fun things at home. My oldest says that math is his favorite part of schoolwork (play/recess/PE being his favorite part of school), which is why we haven't needed to address in school work (yet).
