This easy worksheet introduces skip counting by 3s and 10s. Second graders begin by sorting numbers like 9, 12, 18 and 50, 80, 100 into the correct counting group. Next, five fill-in-the-blank questions practice sequences such as 3, 6, 9, ___, 15 and 30, 40, 50, ___, 70, with one trickier 3s pattern starting at 15, 18, 21. The sheet finishes with four true or false statements that ask kids to spot patterns like 10, 20, 30, 40 versus mixed-up sequences. Sorting, completing, and checking sequences helps build the rhythm of 3s and 10s that supports later multiplication work.