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).

[Q]: What is prob of picking 3 o and 1 p when four letters picked without replacement from pooooopppppoo?
[A]: 42/143


[Q]: Calculate the least common multiple of 21 and (-3 - 7/(-2))*10.
[A]: 105


[Q]: How many millilitres are there in 21/2 of a litre?
[A]:
10500