Etc. Feet is usually written as ft or '. Inches is spelled as in "or." 3'6" would be 3 feet 6 inches, for example. When writing out distances with feet, use commas to separate the value of each foot. So, if you want to write "3 feet 6 inches", then you should write that as "3, 6" inches. Commas are used to divide up numbers too: "12,345.56" = 1,234,567.00. Feet and inches are equivalent units, but different systems can be used to measure them. The English system uses 12 inches as a foot and 0.4 inches as an inch. The metric system uses 100 centimeters for a foot and 2.54 centimeters for an inch. As you can see, there are many ways to express measurement in words. When writing out distances, use commas to separate the value of each foot. For example, if you wanted to write that Tom is three feet six inches tall, you could say that he is 3', 6" tall. Or you could say that he is 33 inches tall. It's your choice! In general, when measuring things, use whole numbers for feet and fractions for inches.