### We all make mistaks

Did you hear about the maths teacher who showed her class how to find the length of the circumference – emphasising the fact that you use 2 x pi x radius to equal (e.g.) metres for feet. She then did a circumference problem for the class, using the wrong formula – instead using the area of a circle formula (area = pr x radius squared) which resulted in a metres squared result. Not one student noticed that the wrong formula and wrong result had occurred!