Why maths teacher said that 420 420 for thief?

The phrase "420 for a thief" refers to the Indian Penal Code (IPC) Section 420, which deals with cheating and dishonestly inducing delivery of property. In a humorous context, a maths teacher might use this phrase to illustrate a mathematical pun or to engage students by linking a serious legal concept with a light-hearted joke. This play on Words combines teaching with a cultural reference, making the lesson more memorable.