4 Pics 1 Word Level 719

Answer:
Formula
Hint
What is the answer to the 4 Pics 1 Word level with A board with different numbers and letters on it, A baby drinking out of a bottle, A water drop with H2O written inside, and A race car?

Hint
What is the answer to the 4 Pics 1 Word level with A board with different numbers and letters on it, A baby drinking out of a bottle, A water drop with H2O written inside, and A race car?