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]: Calculate prob of picking 1 c and 3 d when four letters picked without replacement from {i: 2, h: 4, k: 3, c: 6, d: 3}.
[EX A]: 1/510

[EX Q]: What is next in 30, 29, 26, 21, 14, 5?
[EX A]: -6

[EX Q]: Calculate prob of picking 1 l and 1 w when two letters picked without replacement from kxxvwxwxxxlxxxxwk.
[EX A]:
3/136