[
  "Break 90 into factors: 90 = 10 x 9. Then 2.07 / 90 = 2.07 / 10 / 9.",
  "2.07 / 10 = 0.207. Then 0.207 / 9 = 0.023.",
  "Answer: first blank = 2.07, second blank = 10, third blank = 9, fourth blank = 0.023."
]