The best way to do this is to create a Dynamic Group of your Under 5's and then use your Manage Register to view the attendance and pattern.
Firstly - Go to Reporting>Data Digger, from the first dropdown choose "Under 5's" (near the bottom of the list), click the figure that comes up in the blue circle and give this a name. Click Create Dynamic Group to save this.
Secondly - Go to Register > Manage register, pop in the date you want to view and from the Dynamic Group dropdown choose your Under 5's group, finally, click view register.