On Slopes of Cancellable Numbers

A cancellable number (CN) is a fraction in which a decimal digit can be removed (“‘canceled”) in the numerator and denominator without changing the value of the number; examples include \(\frac{64}{16}\) where the 6 can be canceled and \(\frac{98}{49}\) where the 9 can be canceled. We show that the slope of the line of a cancellable number need not be negative.