The Calculation Helper Abacus is a teaching material that helps children understand addition and subtraction up to 20. It can be used instead of number blocks. It's small enough to fit in a contact bag, making it easy to carry around. This abacus was created through trial and error while working with children who struggle with math, aiming to make something that is easy for children to use and helps them understand quantities. For detailed instructions, search "How to use the Calculation Helper Abacus" on YouTube. The beads are strung on elastic, allowing you to use the stretch of the elastic to create groups of numbers. Flat beads are used, making the beads easy to move. We hope that children can experience the joy of finding the answers themselves, and that this will be of some help to parents and teachers in the field. ◎ "Calculation Helper Abacus" x 1 Available for immediate purchase without comment. ◎ For those in a hurry or who prefer anonymous shipping, we will ship via Rakuraku Mercari Delivery for an additional 100 yen. Please let us know in the comments. ◎ We are accepting orders for a making kit on a separate page. ◎ Size of the Calculation Helper Abacus → 4.5cm x 20cm Materials → Flat beads, plastic corrugated board, elastic Compact, lightweight, and durable, it can be carried in a contact bag. As it is handmade, there may be some slight misalignments or distortions. Please understand this before purchasing. ◎ Although sales images appear on Amazon and other sites, we are only selling on Mercari. #CalculationHelperAbacus #HelperAbacus #20BeadAbacus #SpecialNeedsEducation #AdditionWithCarryOver #SubtractionWithBorrowing #CherryPickingCalculation #EducationalToy #HandmadeTeachingMaterial #100BeadAbacus #SpecialNeedsClass Type...Numbers