question: Terri is knitting a sweater with two sleeves, a collar, and a decorative rosette. The body of the sweater takes 900 stitches to complete, the collar takes a tenth of that number of stitches, and the rosette takes twice as many as the collar. The whole sweater is an 1800-stitch project. How many stitches does each sleeve take?
answer: The collar takes 900 / 10 = <<900/10=90>>90 stitches.
  The rosette takes 2 * 90 = <<2*90=180>>180 stitches.
  The body, collar, and rosette together take 900 + 90 + 180 = <<900+90+180=1170>>1170 stitches.
  Thus, the sleeves take 1800 - 1170 = <<1800-1170=630>>630 stitches.
  Thus, each sleeve takes 630 / 2 = <<630/2=315>>315 stitches.
  #### 315