Explore the relationship between Numberblocks One through Ten by adding or subtracting One to find a new Numberblock friend. These 2-piece, self-correcting puzzles perfectly illustrate the power of Number Magic! Introduce adding and subtracting with your children''s favorite Numberblocks One through Ten characters. Self correcting puzzles are great for practicing early addition and subtraction from 1 to 10. Each set includes 20 self correcting puzzles explaining adding and subtracting by one. As your little one works from preschool to kindergarten, the Numberblocks Adding and Subtracting Puzzle Set is a great way to make learning fun and help with the transition. From the friendly TV series Numberblocks, an award-winning show from BBC, the Numberblocks crew brings math learning to life with the officially licensed Numberblocks Adding and Subtracting Puzzle Set! Numberblocks is helping millions of children around the world to fall in love with numbers, master key math skills and discover the joy of learning.