Question

Would you consider this to be a bug, or to be expected behaviour?

Consider the following

  1 * (2/(1+2))

  equals 0

  1 * ((double)2/(1+2))

  equals 0.6667

Answer 1

This is not a bug. Arithmetic operations where all operands are int yield an int as result.
This is also documented in the MSDN:

When you divide two integers, the result is always an integer. For example, the result of 7 / 3 is 2. To determine the remainder of 7 / 3, use the remainder operator (%). To obtain a quotient as a rational number or fraction, give the dividend or divisor type float or type double. You can do this implicitly by expressing the dividend or divisor as a decimal by putting a digit to the right of the decimal point