As mentioned in previous stories, the city of London is divided into zones. The city centre is Zone 1 and the farther from the city is, the bigger the zone number is. The fare of moving within a zone is the cheapest and the longer distances we take tubes, the more expensive the fare is.
My house is in Zone 4 and the workplace is in Zone 3. My fare seems cheap but it isn’t. Because I have to take tubes through Zone 1. If I go to Zone 3 through Zone 1, I have to across 6 zones, so it is expensive.