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).

What is 15/4 of a millisecond in microseconds?
3750

Calculate prob of sequence ggt when three letters picked without replacement from {t: 12, g: 6}.
5/68

Let b be 4 + -1 + 72490/16. Let r = 4524 - b. Find the common denominator of 4 + -2 - (-83)/(-4) and r.

8