Lesson objective: Understand that numbers have different values when rounded to different places.

Students bring prior knowledge of rounding whole numbers to the nearest 10 or 100 from Grade 3 (3.NBT.A1). This prior knowledge is extended rounding numbers to the hundred thousand as students round numbers to different place values. A conceptual challenge students may encounter is when rounding numbers there can be different values associated with the number when rounded to different places.

The concept is developed through work with a comparison of numbers and place value which is shown through a competition for video game sales.

This work helps students deepen their understanding of number because students will develop number sense by using numbers flexibly when rounding the same number to multiple places.

Students engage in Mathematical Practice 6 (attend to precision) as they use clear definitions in discussion with others. Students will round efficiently to express values and use precise language in explaining how they used place value concepts to find their answer.

Students engage in Mathematical Practice 8 (look for and express regularity in repeated reasoning) as they notice repeated patterns in place value. Students will use number lines to identify benchmark numbers, midpoints and locate the number on the number line and determine the resulting rounded value.

**Key vocabulary:**

- place
- place value
- round
- tie

**Special materials needed:**