Resident Evil 1 - V-Jolt Formula

You will use the scribbling on the wall to figure out how to make the V-Jolt Formula.  

Something is written on the wall
1+2=3, 3+4=7, 2+4=6, 6+7=13, 13+3=16

There are 3 chemicals in the room: Water (#1) Umbrella # 2 and Umbrella #4

There are four empty bottles in the room but you only need to grab three.

Fill one of the bottles with water from the sink and one with Umbrella # 2.

Combine #1 and #2 to make # 3

Fill a bottle with Umbrella # 4. Combine Umbrella #4 with #3 to make #7.

Fill a bottle with Umbrella #2 and a bottle with Umbrella # 4 and combine the two to make #6.

Combine #6 and #7 to make #13.

 Fill a bottle with Water(#1) and Umbrella #2 and combine to make #3.

Finally, combine #13 and #3 to make V-Jolt.

The V-Jolt can be used in the basement where the sharks are to destroy the roots of Plant 42.