In Topic F, students multiply by multiples of 10. To solve a fact like 2 × 30, they first model the basic fact 2 × 3 on the place value chart. Place value understanding helps them to notice that the product shifts one place value to the left when multiplied by 10: 2 × 3 tens can be found by simply locating the same basic fact in the tens column.
In the subsequent lesson, place value understanding becomes more abstract as students model place value strategies using the associative property [2 × 30 = 2 × (3 × 10) = (2 × 3) × 10]. The final lesson focuses on solving two-step word problems involving multiples of 10 and equations with unknown quantities. As in Lesson 18, students estimate to assess the reasonableness of their solutions
This module shows how to decompose multiples of ten to multiply.
