This Problem Set is a part of the Lesson 14, Unit 3, Grade 3. This lesson reviews patterns in the nines fact sequence that were introduced in the previous two lessons. Students examine the 9 = 10 - 1 pattern for multiplication using arrays and think about how the tens digit in the product of a nines fact (? 90) is 1 less than the multiplier and that the ones digit in the product is 10 minus the multiplier.