Sturdy Numarkasten! This "see, touch, and understand" educational material is perfect for Montessori and STEAM learning to eliminate stumbling blocks in math. My children (2 and 4 years old) actually use this! ■ Features of this product ・Sturdy resin case ・The golden ratio is engraved on the back of the box ・The size of the box itself is also the golden ratio. ・Slide-type lid that clicks into place ・By sliding the lid only halfway, you can hide how many balls are on one side ・You can roll the balls with the lid closed ■ Contents ・Numarkas body [brown] ・25 balls [blue marbles] Please comment before purchasing. Size (approx.) Width 15, Length 10, Height 3cm Numarkas Early childhood education Educational toys Nature Science Please refrain from purchasing if you are concerned about the details, as this is a private sale. We offer discounts for multiple purchases and repeat customers, so please comment. Popular keywords... Shichida method Type... Numbers