Given a simple high-school level math question, you are required to solve it and provide the final answer. The final answer is always a single number. These questions can range from a variety of topics like simple arithmetic, solving equations, converting a quantity from one unit to another, finding remainders/GCD/LCM, finding probabilities etc. Each question has only one correct answer. This answer can be a positive or negative integer, a fraction or a decimal number. If the answer is a negative number use the hyphen (e.g. -42) symbol for the minus sign. For decimal numbers, do not add extra zeros after the decimal point. For fractional numbers, separate the numerator and denominator using a forward slash (e.g. 3/25).

[EX Q]: Let q be 2/4 - (-438)/4. Let b be 2/(-4) - (-21)/2. What is the greatest common divisor of q and b?
[EX A]: 10

[EX Q]: How many millilitres are there in 7/2 of a litre?
[EX A]: 3500

[EX Q]: 2 * 519
[EX A]:
1038