This center includes 15 lettered cards with a skip counting rule to follow either by 2s, 5s, and 10s and what number to start with. It comes with a recording sheet and 5 mini 100 charts for students to use as a reference. Students can work in a small group by passing out the cards and recording sheet. They go in letter order, writing out the correct number pattern.
I am also going to use this in a whole class activity with 3 or 4 groups. Students are going to get a card and use their white boards. Each member will write one number following the rule. Then they will stand in front of the class in a line and the class will have to guess their rule.