| 摘要 |
<p>The educational toy has a cylindrical body (1) on which segments (2), which are marked with numbers and arithmetic signs or letters, can move. The segments are threaded on to the body so that they are juxtaposed and can be positioned in any position. The segments are held on the body by friction and the end elements (3,4) can be fixed in position. The body can have a longitudinal rib on which teeth inside the segments engage.</p> |
