Visual Basic Divide Double Randomly based on Divisor

Ok, so I want to divide a number randomly not evenly... so lets say we have 20 I need 5 (Divisor) random chunks of 20.

4 4 4 4 4

Instead I want something like

6 2 4 3 5

It cant exceed the starting number

How can this be accomplished in vb?

Please help, Been stuck for hours.