Math: Counting to 105: Number sequencing Level 1: Pre-k, K, 1st & 2nd Grade. This resource will help your students count to 105 by filling in the missing number. There are just enough clues to help guide your young students to be successful. Each page consists of 15 numbers and 7 or 8 blanks. This is a great activity for classwork, homework, math centers and extra support.