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]: Suppose -27 = g - 70. What is the units digit of g?
[EX A]: 3

[EX Q]: Let t be 4 + -2 + 1/1. Let z = -1 + t. Solve z*q - q = 0 for q.
[EX A]: 0

[EX Q]: Calculate prob of picking 1 r, 2 g, and 1 c when four letters picked without replacement from {c: 1, g: 3, x: 10, r: 1}.
[EX A]:
1/455