It is because the highest number in the negatives, -3 3/4, is always the lowest. Obviously if there is no negative sign it is positive. 1 1/8 is the only positive so it is the greatest. And -2 1/4 is lower that -3 3/4. So it is higher than -3 3/4 but lower than 1 1/8.
I'm sorry I'm not the best explainer, but does this help?</span>
