When do spell out a number?

When a CFG is termer to be ambiguous? What is the circumference of a pool ball if the diameter is 2 inches? How many times does 8 go in to 90? What is the surface area of this cylinder that has a radius of eleven inches and a height of eleven inches rounded to the nearest whole number? What is the adverb for always? How many curved surfaces has a cone got? What is 9x54? What is 40 precent as a decimal and a fraction? How do you convert 45 ft to yard's? What is 1 thirds plus 1 four's? Make 37.5 percent into a fraction? Can two expressions be equal but not equivalent? What is the median of 49 62 and 31? How many minutes and seconds are there in 321 seconds? What is 48 divided by 4.5? Twin prime numbers? Which expression means A number minus 4? Which line is the high side thick or the thinner one? How do you write a fraction as a decimal and a percent? What is a shape that has no edges?