Sin(2theta - pi/2) = - 1

What kinds of numbers have an odd number of factors?

Rachel reads 1/5 of the pages of a book plus 12 pages on the first day. on the second day, she reads 1/4 of the remaining pages plus 15 pages. on the third day, she reads 1/3 of the remaining pages plus 18 pages. on the fourth day, she reads the remaining 70 pages. how many total pages are in the book?

Divide the following fractions 3/4 ÷ 2/3 1/2 8/9 9/8 2