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).

Suppose 2*n + 2*n = 4. Suppose -n = f - 2. What is the highest common divisor of f and 5?
1

Suppose 56 = 113*r - 109*r. Let z = 22 - 10. Calculate the smallest common multiple of z and r.
84

What is fifty-four fifths of a litre in millilitres?

10800