Objectives: Students will learn how to estimate decimal sums as well as use a number line and place value to round decimals.
1. Write the starter up on the board (Round to the nearest whole number) page 121
2. Draw a number line by tenths from 4.0 to 5.0 on the white board. Plot a point at 4.7 and ask discussion questions (math talk) pg 294
a. 4.7 is between which two whole numbers? 4 and 5
b. What number is exactly halfway between 4 and 5? 4.5
c. Is 4.7 to the right or to the left of 4.5? to the right
d. Is 4.7 closer to 4 or closer to 5? Closer to 5
e. What is 4.7 rounded to the nearest whole number? 5
3. Plot a point at 4.4 and 4.5 explaining that a number that is exactly halfway between two numbers always rounds up.
4. Draw a number line by hundredths from 1.60 to 1.70
5. Plot a point at 1.62 and 1.65, etc.
6. Write 8.057 on the board, go over place values and why the tenths place decides the whole number (5)
a. What digits would have to be in the tenths place for it to round to 9? 6,7,8,9
7. Have students do activity on page 121, go over 1-3 as a whole group
8. Move onto estimated sums write 7.934 + 5.825 on the board (8+6=14)
9. Tell students an estimate is a general approximation, and can help on tests
10. Have students pair up and work on page 122
11. Count students off by 7’s and group them for the rounding matching game (10-15 minutes)
12. Have students work on homework (5-10 minutes)