solve · untie

1. Origins, structure, and basic meaning

• Structure: The on readings of 解 are かい and げ, and its kun readings are とく, とかす, and とける. It has 13 strokes and relates to solving a problem or untying something.
• Basic usage: 解く is read とく, and 解ける is read とける.

2. Common pitfalls and similar expressions

• 解く and 解ける
  • 解く means solve or untie.
  • 先生は難しい方程式を黒板で解いた。 means “The teacher solved a difficult equation on the board.”
  • 解ける means to come undone or to be solved.
  • 固く結んだ靴ひもが歩くうちに解けた。 means “My tightly tied shoelace came undone while I was walking.”