A more thorough explanation:

Robbery is a type of crime that involves taking someone's property without their permission and using force or threats to do so. This is against the law and can result in serious consequences for the person who commits the crime.

• A person walks up to someone on the street and demands their wallet while holding a knife. This is considered robbery because the person used force (the knife) and threatened the victim to take their property (the wallet).
• Breaking into someone's home and stealing their valuables while they are away is not considered robbery, but rather burglary.

The examples illustrate the definition of robbery by showing how force or threats are used to take someone's property. In the first example, the person used a knife to intimidate the victim into giving up their wallet. This is a clear example of robbery. In the second example, although property was taken, there was no use of force or threats, so it is not considered robbery.