This worksheet is ideal to use when you wish to test your primary students if they know the spelling of numbers. It goes from number 1 to 100 and, as you can see, it is pretty simple to explain how it is done. It has only one exerceise, but, for students aged from 5 or 6 to 8 or 9 years old seems to be adequate enough to keep them busy for about 10 to 15 minutes, depending on the number of students you have in your classroom.