Missing Addend Sums no More than 20: Grade 1 Addition Worksheets

These worksheets by ArgoPrep continue to have students work with algebraic thinking by completing addition problems with a missing addend sum under 20. These worksheets will have students continue practicing working with addition problems that are missing an addend, but which include the answer. In this case the problems have sums that are under 20, such as 8 + __=19, or 7+__=17. Students will be challenged to complete these worksheets and grow their skills in algebraic thinking by finding the missing addend rather than the answer.