Teaching the Common Core Math Standards With Hands-On Activities, Grades 3-5 (62 page)

Closure

Discuss the answers of the clues and the comparisons. Instruct your students to create a row of clues of their own. Have them exchange their clues for the clues of a partner and find the number.

Answers

(1)
3,245
(2)
30.879
(3)
2.718
(4)
4,927.3
(5)
2.034
(6)
2.718 Comparisons:
(1)
(2)
(3)

Number Clues

After you have found the number for each row, do the following:

1.
Compare the largest number with the next largest number using the
symbol.

2.
Compare the smallest number with the third largest number using the
symbol.

3.
Compare the numbers that have the same value using the
symbol.

Number and Operations in Base Ten: 5.NBT.4

“Understand the place value system.”

4. “Use place value understanding to round decimals to any place.”

Background

Rounding numbers is a useful skill, particularly for estimation. Following are rules for rounding:

• Find the digit in the place you must round to.
  
• If the digit to the right of the digit to be rounded is 5 or more, add 1 to the digit you are rounding. Change any digits to the right of the rounded digit to zero.
  
• If the digit to the right of the digit to be rounded is less than 5, the number you are rounding stays the same. Change any digits to the right of the rounded digit to zero.
  
• If 9 is in the place you are rounding, and the digit to its right is 5 or more, add 1 to the 9. Because
  write 0 in place of the 9 and add 1 to the digit to the left. If the digit to the right of 9 is less than 5, the 9 stays the same. Change all digits to the right of the rounded digit to zeros.
  
• After rounding a decimal, delete any zeros that are not placeholders. (Be sure that students understand that there must always be a digit, even if it is zero, in the place they are rounding to.)
  

Activity: Round the Number

Working in groups, students will play “Round the Number.” They will follow the directions on cards that ask them to round decimals to a specific place.

Materials

Scissors; reproducible, “Round the Number Game Cards,” for each group of students.

Procedure

1.
Review the rules of rounding with your students, as noted in the Background. Provide examples, such as the following:

• Round 4.732 to the nearest tenth. Answer: 4.7
  
• Round 0.958 to the nearest hundredth. Answer: 0.96
  
• Round 81.396 to the nearest hundredth. Answer: 81.40
  

2.
Distribute copies of the reproducible. Explain that it contains 20 cards, each with a number to be rounded to a specific place.

3.
Explain the game. Students are to cut out the cards and place them face down. Students in a group play against each other. Each will take turns selecting a card. All of the members of a group are to follow the directions on the card and round the number to the place indicated on the card. Students will record and compare their answers to determine who is correct. Each student receives a point for every correct answer. If students disagree and cannot determine who is correct, you will serve as the referee.

4.
Explain that the game is over when time is called or students have completed all of the cards. The winner in each group is the player who has the most points at the end of the game.

Closure

Announce the rounded numbers so that students can verify the winners of their groups. Discuss any numbers that students found confusing or difficult to round. On another day, have groups write their own game cards, exchange their cards with another group, and play another game of “Round the Number.”

Answers

(1)
2.5
(2)
4
(3)
19.8
(4)
8.03
(5)
25.90
(6)
7
(7)
810
(8)
300
(9)
6,827.16
(10)
15.3
(11)
5.1
(12)
17.83
(13)
1,000
(14)
62.00
(15)
10
(16)
720
(17)
100
(18)
8,910
(19)
341.1
(20)
10,000

Round the Number Game Cards