Leader Joy Montessori USA Montessori Math Materials Subtraction Strip Board for Preschool Early Learning Tool IMPROVE THINKING SKILLS:Let the baby pass printed numerals red and blue wooden strips learning for addition, subtraction, multiplication and division. WOODEN BOARD:printed numerals (1-18) red and bule wooden strips with numarals(9-18) various lenghts wooden box. MATERIAL : Our products material make by AA level beech wooden ,which import from Bavaria Germany.it has many virtues of beautiful grain,even texture and hard. WORKMANSHIP:we have professional ,fat salary craftsman team, who have been work for premium educational toy more than 8 years. Every one know the detail technological process. AFTER SALES SERVICE: we can supply for free small accessory within 3 year after customers purchase products. If appear buyer receives goods and it was damaged (not human factor).