its simple.
Calculations for serial dilution:
c?v?=c?v?
c1 is concentration of current solution you will use
v1 is volume of current solution used
c2 is concentration of new solution you want to make
v2 is volume of new solution you want to make
So, for example I want to make 10 cubic cm of 5% sucrose solution by using 10% sucrose solution. I need to know how much of 10% to use.
10V? = 5 x 10
V? = 5 ml
So you will take 5 ml of the 10% sucrose solution given and add 5 ml of water so that it makes a final volume of 10 cubic cm. Then shake gently before you do anything with the 5% solution.
hope i helped.