Display the Decimal Place Value Chart Master. Ask students to refer to Check-In: Question 12 in the Student Guide. Invite students to come to the display and write the standard form for each number represented in A–D on the place value chart. See Figure 7.
After all of the numbers have been displayed ask the students to look at the digit in each number that was recorded.
- Describe the difference in the value of the digit “1” in the number 6,183 with the value of the digit “1” in the number 6.183. (Possible response: The value of the 1 in 6,183 is one hundred and the value of the 1 in 6.183 is one-tenth.)
Remind students that each time you move a number one column to the left on a place value chart it is ten times larger. So if you move the 1 from the tenths column to the ones column that is the same as multiplying 0.1 × 10. If you move another place to the left to the tens place you will have moved 2 places to the left and would multiply by ten again. This can be represented with the number sentence 0.1 × 10 × 10 or 0.1 × 100.
- If you move the digit “1” from the tenths column to the hundreds column, how many places to the left will you move? (3)
- What is the value of the digit “1” when it is in the hundreds column? (100)
- What number sentence can you write to represent how the value of the digit “1” changes when you move from the tenths column to the hundreds column? (0.1 × 10 × 10 × 10 or 0.1 × 103 )
- Describe in words what happens to the value of a digit as you move to each column from right to left on a place value chart. (Possible response: Each time a digit moves a column left on the place value chart it is ten times larger than it was in the column to the right.)
- How can you use this information to describe what will happen to the value of a digit if you move it from left to right on the place value chart? For example, what will happen to the value of a digit in the hundreds column if you move it to the tens column? (Possible response: It will be ten times smaller or 1/10 as much as it was in the column to the left.)
