👉 In the context of mathematics, a "fifteenfold" refers to the number 150. This is because it can be calculated as follows: \[ 150 = \frac{15}{1} + \frac{15}{1^2} + \frac{15}{1^3} + \frac{15}{1^4} + \cdots + \frac{15}{1^{15}} \] This is fifteenfold