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).

[Q]: Calculate prob of picking 1 t, 1 k, and 1 z when three letters picked without replacement from {t: 1, z: 2, k: 1}.
[A]: 1/2


[Q]: How many millilitres are there in 9.081666 litres?
[A]: 9081.666


[Q]: Suppose o - 3 = 3. Calculate the highest common factor of 42 and o.
[A]:
6