2/5
a
b
To get the number of factors, simply take each item from the expression and isolate it. Given the formatting limitations, I can't write the factor 2 over 5 and will instead represent it as 2/5.
So the expression is
2/5ab
where there's an implied multiplication between all the factors. Making that multiplication explicit, the equation becomes
2/5 * a * b
And each possible factor also becomes quite explicit. Namely, the factors are
2/5
a
b
The reason that the 2 and 5 aren't considered factors is because technically, you could consider the 2 to be a factor, there isn't a corresponding factor of 1/5. So you have to consider 2/5 to be a single entity.
