Scientific Magic Series Mental Arithmetic Dice-Magic Mental Arithmetic Master

*Product color is shipped randomly Let you calculate the sum of all dice in seconds! Mental arithmetic tricks - add the ones digits of 5 dice to get the tens digit and ones digit of the answer, and then subtract the number just obtained from the "key number 50" to get the thousands digit and hundreds digit of the answer number of digits! https://5993.cyberbiz.tw/s/files/5993/ckeditor/pictures/content_f3d7b919-512d-46df-b666-902b493f6ee5.jpg https://5993.cyberbiz.tw/s/files/5993/ckeditor/pictures/content_39743587-7b24-4c81-859a-8b877cdb6549.jpg https://5993.cyberbiz.tw/s/files/5993/ckeditor/pictures/content_06264b81-7abe-4b7d-b689-f1b544bb4d01.jpg https://5993.cyberbiz.tw/s/files/5993/ckeditor/pictures/content_ca311317-0806-4802-b6ce-15652b80e937.jpg <Science Trivia> Mental calculation is a calculation method based on personal thinking without using calculation tools, also known as brain calculation. Therefore, there is the so-called combined teaching of three calculations. These three calculations refer to abacus calculations, pen calculations, and brain calculations. There are also other tools that are used in training, such as abacus, formulas, movements, etc. Training to the point where you don't need tools in hand is like calculating with a tool in your hand, such as abacus mental arithmetic. (Reposted from: wikipedia) Product Specifications: ► Contents: five mental arithmetic dice ► Dimensions: 3 x 3 x 3 cm (single piece) ► Material: Resin ► Manufacture: Taiwan Precautions: ► 1. Keep away from fire