This is another example of combination system equation with overall 3 unknown values that have been very popular lately. To solve it we need simple math and logic skills. The first line usually consist of 3 same popular chemical compounds. So we need to divide the number at the end of the equation by 3 to find the value of the first compound. The second line include always one of the first chemical compounds and another two same chemical compounds. So we subtract the value of the first compound from the number at the end of the equation and then divide the result by 2. Now we have the value of the second compound. The third line include one compound from the second line and again two new chemical compounds, but in different order. Then again we subtract the the value of the second compound and devide the result by 2. When we have the values of all 3 chemical compounds, the last fourth line is to add them to one another by simple addition and find the missing number. This app include the following chemical compounds: Water, Salt, Methane, Soda, Acetone, Ammonia, Bleach, Steel and Ethanol.