Master adding two-digit numbers and multiples of 10 with these engaging, no-prep Grade 1 math worksheets! Perfect for math centers, independent practice, or morning work. This resource helps students visualize adding tens to double-digit numbers using base-ten strategies. Aligned to 1.NBT.C.5, it included differentiated practice pages and answer keys to save you precious prep time. This resource is a 100 pages (50 student practice pages + 50 answer keys pages) engaging with concept of stren