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: Let c be (5 + -4)/((-1)/3). What is the tens digit of c - (-6)/3 - -13?
Example Output: 1

Example Input: What is the value of ((-2)/(-98)*35)/(3/21)?
Example Output: 5

Example Input: Solve -31*k + 34*k + 4*i = 6, -10 = -5*k - 4*i for k.
Example Output:
2