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]: Three letters picked without replacement from {s: 5, f: 4, l: 1}. What is prob of picking 2 f and 1 l?
[EX A]: 1/20

[EX Q]: How many millilitres are there in 442.2491l?
[EX A]: 442249.1

[EX Q]: Let w be -2 + (0 - -1*2). Let d be (80/(-5))/(2/(-2)). Suppose -2*q - q + 31 = -5*r, w = -2*q - 4*r - d. What is the units digit of q?
[EX A]:
2