Now, there are 360° in a circle, how many times does 360° go into 1860°?
well, let's check that,

now, this is a negative angle, so it's going
clockwise, like a clock moves, so it goes around the circle clockwise 5 times fully, and then it goes 1/6 extra.
well, we know 360° is in a circle, how many degrees in 1/6 of 360°? well, is just 360/6 or their product, and that's just 60°.
so -1860, is an angle that goes clockwise, negative, 5 times fully, then goes an extra 60° passed.
5 times fully will land you back at the 0 location, if you move further down 60° clockwise, that'll land you on the IV quadrant, with an angle of -60°.
therefore, the csc(-1860°) is the same as the angle of csc(-60°), which is the same as the csc(360° - 60°) or csc(300°).
Alright, so the first thing I would do is find the LCM of the dividends, which is 20. So we have 10 15/20 and 6 16/20. You can either leave it there and just carry the one (20 in this case) for 3 19/20.
If you multiply 10 by 20 and add 15, or 6 by 20 and add 16 (which I think is easier) you get 215/20 - 136/20 = 79/20. It can be simplified from here if you teacher wants it in the future.
A. place a closed circle on -4 and shade to the right.