北师大初一数学七年级上册

点一下: https://www.bilibili.com/video/BV1kC4y1a7Cd?t=806.3 https://www.bilibili.com/video/BV1sz411v79k?t=123.9&p=16
2-11科学计数法 P16 - 02:22
点一下: https://www.bilibili.com/video/BV1kC4y1a7Cd?t=806.3 https://www.bilibili.com/video/BV1sz411v79k?t=123.9&p=16