Webinars SET B - Grade 1-2 - Sunday@5:45-6:45pm EST-Recording Webinar 7

Video Transcription

Video Summary

The webinar focuses on solving competition-style problems about 3D shapes, especially cubes. The instructor begins with session rules (cameras/mics off, ask questions via chat) and introduces a four-step problem-solving method: understand the question, plan, carry out the plan carefully, then check and reflect. A brief review of the previous lesson on age word problems emphasizes identifying key information (current age, time changes, relationships like older/younger) and practicing full timed tests (75 minutes) ahead of the upcoming competition.<br /><br />The main lesson contrasts 2D “flat” shapes with 3D “solid” shapes that have height and depth, and introduces key 3D vocabulary: faces, edges, and corners. Students practice identifying common 3D figures (cube, sphere, cylinder, cone, rectangular prism, pyramid) versus 2D shapes. Several poll questions train spatial reasoning: determining what parts of stacked rings or cube structures are visible from different viewpoints; counting cubes including hidden ones; finding how many cubes are unseen using subtraction; comparing structures to decide which has the most cubes; and deciding which shape cannot be built from given blocks.<br /><br />A major focus is cube nets and “opposite faces” (opposite faces never touch). Students solve a five-point problem by identifying which sticker must be opposite another using adjacency to a common face. Another challenge involves counting exposed faces to minimize paint on glued cube arrangements, including a faster method: each glued connection removes two paintable faces. The session ends with a harder visualization problem involving a painted 3×3×3 cube with corners removed and counting distinct stamp patterns, plus a reminder to practice extensively for the competition.

Keywords

3D shapes

cubes

competition math problems

spatial reasoning

faces edges corners

cube nets

opposite faces

counting hidden cubes

painted cube exposed faces

3×3×3 cube visualization