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).
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Question: Let r(m) = 2*m**2 + 5*m + 2. Let s be r(-3). Let y(l) = l. Let n be y(s). Suppose d - n = -2*a, -4*d - 3*a + 18 = -d. What is the units digit of d?

Answer: 7


Question: How many millimeters are there in 52138.89 kilometers?

Answer: 52138890000


Question: Suppose -a - 4*i + i - 13 = 0, 2*i + 10 = 0. Suppose a = -5*g + l, 4*l - 10 = -2. Suppose 2 = 5*j - 2*q, -j - 2*q + 13 - 3 = g. Solve -j*k = 3*k + 5 for k.

Answer:
-1