These are Number Sense Charts from 1-20. Each Chart has missing numbers for a student to complete. This helps students increase their Number Sense with numbers up to 20. There are 15 pages, increasing in difficulty from simple (3-4 missing numbers) to difficult (most numbers missing). The final page is a blank chart. These are great to laminate and make differentiating easy. They can be used as homework, classwork, or in a math center.