The technique used to make a single dilution is repeated sequentially using more and more dilute solutions as the "stock" solution. At each step, 1ml of the previous dilution is added to 9ml of distilled water. Each step results in a further 10-fold change in the concentration from the previous concentration.
The values shown in the tubes are the amount (in ml) of the stock solution present in each ml of the dilute solution.
The dilution of the original stock solution is shown below the tubes.