This add 8 within 20 worksheet has a set of problems curated to ensure that your child becomes more proficient in addition. Once students have understood the concept of counting, they should learn to add numbers. Add 8 within 20 worksheet provides plenty of practice with addition. This worksheet is about practicing with the horizontal format in which numbers are written side by side. To develop flexibility with numbers and operations, students need to have enough practice in this format and not just rely on the vertical/column method.