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
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Q: What comes next: -37, -72, -129, -220, -357, -552, -817?

A: -1164
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Q: Let f(k) = -k**3 - 8*k**2 - 4*k. Let p be f(-9). Let d = p + 15. Suppose -z - 2 = -14. Calculate the greatest common divisor of d and z.

A:
12
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