Which is not a major expense category?
housing
transportation
electricity
food

Housing is definitely a major expense. Whether you rent or own it is likely to be your largest expense. Electricity and food are absolute necessities. Food is somewhat controllable depending on how often you eat out and the types of groceries you purchase. Electricity is also somewhat controllable depending on your lifestyle and how you manage consumption. However both of these categories are still going to comprise a significant portion of your monthly expenses, Transportation, on the other hand, does not have to be a major expense. If you choose not to own a car, walk or bicycle to walk, work from home, use the internet for shopping, ride share, bum rides from friends and use public transportation as a last resort this expense can be very small. However if you choose to own multiple high end cars this expense can also be quite high and greater than food or electricity. In summary, housing, food and electricity are required to survive in the modern world and will always be recurring major expense items. In contrast, it is possible to choose to minimize transportation so it is not a major expense. Now I write this as someone who owns 4 cars so the best approach is to get an education, work hard and make enough money so you don't have to worry about any of these expenses.

When i did the math i got 11 cm