Free printable addition worksheets for whole numbers ... - Homeschool Math Worksheets for mental addition Missing addend - sums with 9 Missing addend - sums with 10 Missing addend random - sum max 10 Missing addend random within 10 and 20 Complete the next ten Add a 2-digit number and a 1-digit number mentally - within the same ten Complete one hundred (missing addend) Add two 2-digit numbers - one addend is a whole ten