Unit 8
A C T I V I T Y 51
AC TIVIT Y
Rounding Whole Numbers and Money
30 MIN
GROUPS
Show students a picture of the Statue of Liberty. The Statue of Liberty weighs 225 tons.
If I were to ask you about how many tons the statue weighs, what would you say?
Use after
Unit 8, Session 3.9
Students might say:
“It weighs close to 200 tons.”
“It weighs more than 200 tons, but less than 300 tons.”
Vocabulary/Vocabulario
round to the nearest
hundred; ten;
thousand; dollar/
redondear a
la centena, a
la decena, al
millar o al dólar
más cercanos
On the board, draw a number line from 200 to 300. Include a tick mark for each ten,
but only label the marks for 200 and 300.
200
Materials/Materiales
• picture of the Statue of Liberty/
fotografía de la Estatua de la
Libertad
• Activity 51 Master (see below)/
Actividad 51 (ver abajo)
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Activity 51
MASTER
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Un i t 8
How Many Hundreds? How Many Miles?
NOTE Students use a number line
to help them round whole numbers
and money.
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300
Where is the halfway mark between 200 and 300? Let’s circle it. What number
does the halfway mark represent? Have a student write “250” at that mark.
Ask a volunteer to show where 225 is on the number line. To which number is 225
closer, 200 or 300? Since 225 is closer to 200 than it is to 300, we say that 225
rounded to the nearest hundred is 200.
Now have a student label each of the marks between 200 and 300. Which two tens
is 225 between? Then draw a new number line from 220 to 230, with marks for the
ones, but labels for just 220 and 230. Where is the halfway mark? Circle it and have
students write “225” at that mark. Is 225 closer to 220 or 230? Because 225 is at the
halfway mark, we round it to the larger ten, 230. We say that 225 rounded to the
nearest ten is 230.
Extend the discussion to show how to round to the nearest thousand. Provide a variety
of 2-, 3-, and 4-digit numbers for students to round to the nearest ten, hundred, and
thousand.
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Draw a number that extends from $6.00 to $7.00. Include marks to show the dimes.
What is the halfway mark? How could we round $6.87 to the nearest dollar ?
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Use after Unit 8, Session 3.9
Provide money amounts for students to round to the nearest dollar. Have students
describe situations where money is rounded to the nearest dollar.
PR AC TICE
In the Activity 51 Master, students round whole numbers to the nearest 10, 100, or
1,000, and money amounts to the nearest dollar.
DIFFERENTIATION : Suppor ting the Range of Learner s
Draw a number line from 10 to 20. Label 10, 11, 12, 13, and 14 with
blue chalk, and 15, 16, 17, 18, 19, and 20 with red chalk. This number line will help
you decide how to round numbers between 10 and 20 to the nearest ten. A number
in blue rounds to 10, and a number in red rounds to 20. Repeat the idea for
rounding numbers to the nearest hundred and to the nearest thousand.
Unit 8: How Many Hundreds? How Many Miles? Session 3.9 (End-of-Unit Assessment)