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 Input:
Let i = -28 - -30. Suppose 4*z + 5*k = 200, -i*z + 81 = -k - 33. What is the tens digit of z?

Ex Output:
5


Ex Input:
Suppose 4*i + i = 45. Suppose 3*u = i*u - 132. Let v = -82 + 147. Calculate the remainder when v is divided by u.

Ex Output:
21


Ex Input:
Calculate prob of picking 1 v, 1 l, and 2 f when four letters picked without replacement from {l: 1, v: 3, f: 5, c: 1}.

Ex Output:

1/7