Three Part Lesson in Mathematics: Rounding to the nearest 10, 100, and 1000

Here's the 3-part lesson we observed in Iain's classroom.  The whole class, grade threes and fours, did the same lesson.

Part 1: Activating prior knowledge
Students brainstormed all the different ways we use estimation in our lives.  Unfortunately, I did not capture this chart :-( 

But here's what the class talked about at the beginning of the unit.

Part 2: Working on It
Iain introduced the Tim bits problem the class.  Estimating (rounding to the nearest 10) was the goal.  An extension to the problem involved money.

Students had a choice in working alone or with a partner.  Some worked alone while most worked with a partner.

Here are a few student solutions:

Part 3: Consolidation
Iain asked students to form a group to share their thinking and compare it with others.

After this, Iain asked individual students to share what he/she learned from the small group sharing.  This was accountable talk in action!

After each small group shared, Iain moved into the explicit teaching portion of the lesson.  He wanted to reinforce the conditions for rounding to the nearest 10, 100, and 1000. 

In prior lessons, he noticed that his class had difficulty rounding in general (expecially the textbook problems).  But they had no problems with this question.  So he asked them why.  As the class, they discussed how they can think of money to round up and the conditions for rounding down.

Part 4: Independent Practice

Iain chose specific questions from the textbook for the grade 3s and 4s to practice their rounding. 

Students were able to apply what they learned from the 3-part lesson and Iain's explicit teaching right away.

Iain was able to see if students were getting the concept of rounding or if he needed to do more teaching around this concept.