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 {j: 2, y: 2, k: 1, u: 4}. Give prob of picking 2 j and 1 u.
[EX A]: 1/21

[EX Q]: What is prob of picking 4 z when four letters picked without replacement from {y: 3, z: 4, b: 13}?
[EX A]: 1/4845

[EX Q]: Calculate 12/198 - 600/99.
[EX A]:
-6