Rounding Decimals
Comparing and Ordering Decimals
Decimal Place Value
Patterns and Rules
Adding and Subtracting Decimals
Grab Bag
100
Rounding to the nearest whole number is rounding to what place?
The ones.
100
Compare 6.76 and 6.759 using <,>,=.
6.76<6.759
100
____.____ ____ ____
Label these blank place values.
ones, tenths, hundredths, thousandths
100
When writing a rule for a sequence of numbers, how do you know if your rule should be addition or subtraction.
If the pattern increases the rule is to add. If the pattern decreases, the rule is to subtract.
100
What is the most important thing to do when setting up a decimal addition or subtraction problem?
Line up the decimal points/place values.
100
On which two days was the value of 1 Euro the same when rounded to the nearest hundredth of a dollar?
Monday and Wednesday
200
True or false, 0.673 rounded to the hundredths place is 0.68.
False! It's 0.67.
200
Use <,>,= to order these numbers from least to greatest.
0.300
0.3
0.30
0.300=0.3=0.30
Each of these numbers are worth 3 tenths. The zeros hold no value in the hundredths and thousandths places.
200
0.6 is 10 times as much as...
0.06
200
How do you find out how much a pattern is increasing or decreasing by?
You subtract two neighboring terms to find the difference.
200
Estimate and subtract 93.6 - 79.84 =?
Estimate: 14
Actual: 13.76
200
Rafael bought 2.18 pounds of potato salad and 4.2 pounds of macaroni salad to bring to a picnic. Rounded to the nearest tenth, Rafael bought 2.3 pounds of potato salad. True or False?
False; 2.2 pounds of potato salad
300
What place value was this number rounded to? 2.607 turned into 2.61.
Hundredths
300
Order the following numbers from greatest to least:
2.007
2.741
2.09
2.97
2.97; 2.714; 2.09; 2.007
300
What is the word form of 36.290?
Thirty-six and two hundred ninety thousandths.
300
Rick bought 3 yogurt bars at a snack shop. Each yogurt bar cost $1.70.
Complete a table to show the price of 1, 2, and 3 yogurt bars.
1= $1.70
2= $3.40
3= $5.10
300
Troy and Lazetta are solving the following word problem:
Rosalie's cat weighs 9.5 pounds. Her dog weighs 25.2 pounds. What is the weight of both animals combined?
Troy sets up his problem as 9.5 + 25.2. Lazetta sets up her problem as 25.2 + 9.5. Who is correct? Complete the explanation of your answer.
34.7 lbs combined. They are both correct. Addition is commutative which means you can order the numbers in any way and still get the same answer.
300
0.91 is 10 times as much as ____ and 1/10 of ____
Fill in the blanks
0.091; 9.1
400
Choose a group member to recite the whole entire decimal rounding rhyme. You have some time to discuss before I come around.
Find your place, look nextdoor, 5 or greater add 1 more. All the numbers in front stay the same, all the numbers behind get chopped off.
400
Fill in the blank space with a digit that makes the statement true.
2.48> 2.4_ >2.463
7
400
Ms. Cyr wrote the number "four and twenty six thousandths" as 4.26. Describe and correct her error.
She wrote "four and twenty six hundredths." She needs to put a zero in the tenths place so the 26 will shift to the thousandths place, making 4.026.
400
Bob and Ling are playing a number pattern game. Bob wrote the following sequence. What is the rule for this sequence?
29.8, 27.1, 24.4, ____ , 19
Rule: Subtract 2.7
400
Miguel has $25. He spends $7.50 on a movie ticket, $3.65 for snacks, and $1.25 for bus fare each way.
How much money does Miguel have left?
$11.35
400
What is the value of the underlined digit? Tell word form, standard form and expanded notation.
0.664
six hundredths, 0.06, (6x1/100)
500
Stuart said 7.895 rounded to the tenths was 7.900. Is Stuart correct or incorrect?
He is correct, but the way he wrote his answer is not TECHNICALLY correct. When you round decimal numbers you "chop off" all numbers behind the rounded number. Adding 0's to blank place values simply makes an equivalent decimal number, and the value is no different.
500
How is comparing and ordering decimals different from whole numbers? (based on number of digits vs. value of digits)
When you compare and order whole numbers you can look at the number of digits a number has. The more digits, the greater the value. (EX: 1,000 and 100- 1,000 had more digits and is worth more) Decimal numbers can have more digits, but still be of a lezzer value. You have to look at the value of the digits in the greatest place value positions. (EX: 0.100 is less than 0.4- the 0's after the 1 hold no value, 4 tenths is more than 1 tenth)
500
Bobby wrote 25.306 in expanded notation as (2x10)+(5x1)+(3x1/10)+(6x1/100) Is Bobby correct? If he made a mistake, what mistake did he make?
No! He said (6x1/100) it should be (6x1/1000) since the 6 is in the thousandths place.
500
Bob and Ling are playing a number pattern game. Bob wrote the following sequence. What is the unknown term in the sequence?
29.8, 27.1, 24.4, ____ , 19
12.7
500
Yolanda's sunflower plant was 64.48 centimeters tall in July. During August, the plant grew 18.2 centimeters.
Estimate the height of Yolanda's plant at the end of August by rounding each value to the nearest whole number. Will you estimate be less than or greater than the actual answer?
Estimate: 82 cm
The estimate will be less that the actual because I "chopped off" the 0.48 and 0.2. If I had rounded up, the estimate would be more than the actual.
500
Students are selling muffins at a school bake sale. One muffin costs $0.27, 2 muffins cost $0.40, 3 muffins cost $0.53, and 4 muffins cost $0.66.
If this pattern continues, how much will 7 muffins cost?
$1.05