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 sequence nesl when four letters picked without replacement from {a: 1, v: 2, e: 2, n: 1, l: 1, s: 1}.
[EX A]: 1/840

[EX Q]: Calculate 5 - (-4 - 140/(-16)).
[EX A]: 1/4

[EX Q]: Two letters picked without replacement from fxvffzzgzffzzgffxz. Give prob of sequence fv.
[EX A]:
7/306