Step 1 :Translate the English phrase '20 divided by the number' into a mathematical expression. This can be written as '20 divided by x' or '20/x'.
Step 2 :Evaluate the expression for x=5.
Step 3 :Substitute x=5 into the expression, we get 20/5.
Step 4 :Calculate the value, we get 4.
Step 5 :So, the mathematical expression for the English phrase '20 divided by the number' is \(\frac{20}{x}\) and its value for x=5 is \(\boxed{4}\).