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).
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Question: Calculate the least common multiple of 21 and (-3 - 7/(-2))*10.

Answer: 105


Question: Let y be -6 + 56 - 1*-2. Let h(k) = k**3 + 6*k**2 - k + 7. Let l be h(-6). What is the greatest common factor of y and l?

Answer: 13


Question: Three letters picked without replacement from rrrrrrrrrrbrrrrrrrrb. What is prob of picking 1 b and 2 r?

Answer:
51/190