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 k = 5811/122 - 8/61. Let l = 2143/345 + -34/23. Let r = l + -13/45. Calculate the common denominator of k and r.

Ex Output:
18


Ex Input:
Suppose -2*t - 51 = -5*t + 3*l, 37 = 3*t + 4*l. Calculate the common denominator of 1*(308/32 + 3) and t.

Ex Output:
8


Ex Input:
Let z = 7 + 1. Let b = -6 + z. Suppose 0 = m + b*m - 21. What is the units digit of m?

Ex Output:

7


