Adding doubles worksheets 1st grade. Below you will find our grade one worksheets that deal with adding doubles. Adding doubles is a great strategy taught in first grade to add two same numbers. For example, 5 + 5 or 8 + 8. Practicing adding doubles helps grade one students remember addition facts. Once students are comfortable with ArgoPrep's adding double worksheets, students can learn the adding doubles plus one strategy. Download our beautifully designed math worksheets created by teachers!