1. Doubling a negative number keeps its sign, but other than that it's the same as doubling a positive number. -16.5/2 = -8.25
3. Remember PEMDAS. The parentheses here are for purposes of readability, and there are no exponents, so we'll ignore those. MD means multiplication and division in whatever order they come, so 4.2 * -1/3 = -1.4, -1.4/6 = -7/30, -7/30 * -10 = -7/3 or about 2.33.
Make sense? Any questions?
