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: Suppose -g - 4*g = -3*u + 29, 0 = 4*u + 3*g. Suppose -30 = -4*b - s + u*s, -s - 33 = -4*b. What is the units digit of b?

Answer: 9


Question: Two letters picked without replacement from {t: 1, z: 1, v: 1, b: 1, s: 1, p: 2}. What is prob of picking 1 t and 1 p?

Answer: 2/21


Question: Let t = -3027 + 18257/6. What is the common denominator of t and (23 + -21)/(56/186)?

Answer:
42