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).

Example Input: Calculate prob of picking 2 n and 2 o when four letters picked without replacement from {o: 17, n: 3}.
Example Output: 8/95

Example Input: Solve 4*f + 4*z = 0, 0 = -28*f + 29*f - 2*z + 15 for f.
Example Output: -5

Example Input: Let f be (15/(-3))/(2/14). Let u = f - -64. What is the units digit of u?
Example Output:
9