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).

Let b = 40 + -18. Calculate the least common multiple of 42 and b.
462
Let b = 40 + -18. Substituting, we get:
b = 22\n
The least common multiple of 42 and b is given by the formula: lcm(42, 22) = 42 x 22 / gcd(42, 22)\n
Hence, we get lcm(42,22) = 924/2 = 462.