Answer:
6
Explanation:
The word of in math refers to multiplication.
We can convert 15 to a fraction as well so we can use them together (15/1).
x
We can then work diagnolly and reduce the 5 and 15 since they are both divisible by 5- this is also known as the GCF or Greatest Common Factor
x
This is the same as 2 x 3 since both numbers divided by 1 are just themselves.
2x3 = 6