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]: Let q = -7 - -11. Suppose q*l = 6*l. Solve 2*z - 4 = -2*f, l = -0*f + 3*f + z for f.
[EX A]: -1

[EX Q]: Solve 23*o = 21*o - 4*u + 18, 4*o - 2*u + 14 = 0 for o.
[EX A]: -1

[EX Q]: Three letters picked without replacement from {a: 1, s: 2, r: 2, q: 9}. Give prob of sequence arr.
[EX A]:
1/1092