The product rule for variables consist, first, in determining when your product
is between the same variable or not.
If for example you have the following product:
x*y
Here, you only write each variable, just as follow:
x*y = xy
If the product is between the same variables you take into account that you have to sum the powers of the implied variables. If for example you have the following product:
x²*x³
You sum the powers, just as follow:
x²*x³ = x⁵
For the case of number, for two different numbers you simply multiply the implied numbers, as for example:
5*10 = 100
If the number are equals with different powers you proceed the same as the variable case:
5²5³ = 5⁵