For students to master their basic addition/subtraction/multiplication/division facts they should practice them every day. I recommend students practice for 5-10 minutes daily.  And, I suggest students practice in a variety of ways. 
Here are a few ideas, but be creative and invent your own fun ways to practice.

Flash Cards
(I have extras at school if you'd like to borrow some.)

Online Math Games

Fact Dash

Practice with Timed Sheets
(print your own, or I have some available at school)

Write facts in the sand or shaving cream on the table.

Practice multiples by making up songs or poems.

Sing along with the multiplication videos