student learning goal chart
DESCRIPTION
Student Learning Goal Chart. Lesson Reflection. Math Learning Goal Students will understand decimals. Students will understand decimals by being able to do the following:. Learn to write, compare, and order decimals using place value and number lines (3-1) - PowerPoint PPT PresentationTRANSCRIPT
Student Learning Goal Chart
Lesson Reflection
Math Learning Goal
Students will understand decimals.
Students will understand decimals by being able to do the following:
• Learn to write, compare, and order decimals using place value and number lines (3-1)
• Learn to estimate decimal sums, differences, products, and quotients (3-2)
Today’s Learning Goal Assignment
Learn to estimate decimal sums, differences, products, and quotients.
Course 1
3-2 Estimating Decimals
6th Grade Math HW(Sections 3-1, 3-2)
Page 98#1-10 all
Course 1
3-2 Estimating Decimals
3-2 Estimating Decimals
Course 1
Warm UpWarm Up
Lesson PresentationLesson Presentation
Problem of the DayProblem of the Day
Warm UpOrder the decimals from least to greatest.
1. 18.74, 18.7, 18.47
2. 9.06, 9.66, 9.6, 9.076
Write each in words.3. 3.072
4. 6.1258
18.47, 18.7, 18.74
9.06, 9.076, 9.6, 9.66
three and seventy-two thousandths
Course 1
3-2 Estimating Decimals
six and one thousand two hundred fifty-eight ten-thousandths
Problem of the Day
Calculate your age in months.
Possible answer: 11 yr 8 mo = 140 mo
Course 1
3-2 Estimating Decimals
Today’s Learning Goal Assignment
Learn to estimate decimal sums, differences, products, and quotients.
Course 1
3-2 Estimating Decimals
Vocabulary
clusteringfront-end estimation
Insert Lesson Title Here
Course 1
3-2 Estimating Decimals
Course 1
3-2 Estimating Decimals
When numbers are about the same value, you can use clustering to estimate. Clustering means rounding the numbers to the same value.
Course 1
3-2 Estimating Decimals
Additional Example 1: Health Application
Nancy wants to cycle, ice skate, and water ski for 30 minutes each. About how many calories will she burn in all? (Cycling = 165.5 calories, ice skating = 177.5 calories, and water skiing = 171.5 calories)
165.5 170 The addends cluster around 170.
177.5 170 To estimate the total number of calories, round each addend to 170.
171.5 + 170
Add. 510
Nancy burns about 510 calories
Course 1
3-2 Estimating Decimals
Try This: Example 1
Abner wants to run, roller blade, and snow ski for 60 minutes each. About how many calories will he burn in all? (Running = 185.5 calories, roller blading = 189.5 calories, and snow skiing = 191.5 calories)
185.5 190 The addends cluster around 190.
189.5 190 To estimate the total number of calories, round each addend to 190.
191.5 + 190
Add. 570
Abner burns about 570 calories
Course 1
3-2 Estimating Decimals
When rounding, look at the digit to the right of the place to which you are rounding.
• If it is 5 or greater, round up.
• If it is less than 5, stay the same.
Remember!
Course 1
3-2 Estimating Decimals
Additional Example 2: Rounding Decimals to Estimate Sums and Differences
Estimate by rounding to the indicated place value.
A. 7.13 + 4.68; ones
B. 9.705 – 0.2683; tenths
7.13 + 4.68 Round to the nearest whole number.
7 + 5 = 12 The sum is about 12.
9.705 9.7 Round to the tenths.
Align.
9.4 Subtract.
– 0.2683 –0.3
Course 1
3-2 Estimating Decimals
Try This: Example 2
Estimate by rounding to the indicated place value.
A. 6.09 + 3.72; ones
B. 8.898 – 0.4619; tenths
6.09 + 3.72 Round to the nearest whole number.
6 + 4 = 10 The sum is about 10.
8.898 8.9 Round to the tenths.
Align.
8.4 Subtract.
–0.4619 –0.5
Course 1
3-2 Estimating Decimals
Compatible numbers are close to the numbers that are in the problem and are helpful when you are solving the problem mentally.
Remember!Remember!
Course 1
3-2 Estimating Decimals
Additional Example 3: Using Compatible Numbers to Estimate Products and Quotients
Estimate each product or quotient.
A. 33.83 1.98
B. 72.77 ÷ 26.14
35 2 = 70 35 and 2 are compatible.
75 ÷ 25 = 3 75 and 25 are compatible.
So, 72.77 ÷ 26.14 is about 3.
So 33.83 1.98 is about 70.
Course 1
3-2 Estimating Decimals
Try This: Example 3
Estimate each product or quotient.
A. 22.12 4.98
B. 62.31 ÷ 18.52
20 5 = 100 20 and 5 are compatible.
60 ÷ 20 = 3 60 and 20 are compatible.
So, 62.31 ÷ 18.52 is about 3.
So 22.12 4.98 is about 100.
Course 1
3-2 Estimating Decimals
You can also use front-end estimation to estimate with decimals. Front-end estimation means to use only the whole-number part of the decimal.
Course 1
3-2 Estimating Decimals
Additional Example 4: Using Front-End Estimation
Estimate a range for the sum.
7.86 + 36.97 + 5.40
Use front-end estimation.
7.86 7 Add the whole numbers only.
36.97 36 The whole-number values of the decimals are less than the actual numbers, so the answer is an underestimate.
5.40 + 5
at least 48
The exact answer of 7.86 + 36.97 + 5.40 is 48 or greater.
Course 1
3-2 Estimating Decimals
Additional Example 4 Continued
You can estimate a range for the sum by adjusting the decimal part of the numbers. Round the decimals to 0, 0.5, or 1.
0.86 1.00Add the decimal part of the numbers.
0.97 1.00 Add the whole-number estimate and the adjusted estimate. 0.40 + 0.50
2.50
48.00 + 2.50 = 50.50
The adjusted decimals are greater than the actual decimal, so 50.50 is an overestimate.
The estimated range for the sum is from 48.00 to 50.50.
Course 1
3-2 Estimating Decimals
Try This: Example 4
Estimate a range for the sum.
8.92 + 47.88 + 3.41
Use front-end estimation.
8.92 8 Add the whole numbers only.
47.88 47 The whole-number values of the decimals are less than the actual numbers, so the answer is an underestimate.
3.41 + 3
at least 58
The exact answer of 8.92 + 47.88 + 3.41 is 58 or greater.
Course 1
3-2 Estimating Decimals
Try This: Example 4
You can estimate a range for the sum by adjusting the decimal part of the numbers. Round the decimals to 0, 0.5, or 1.
0.92 1.00Add the decimal part of the numbers.
0.88 1.00 Add the whole-number estimate and the adjusted estimate. 0.41 +0.50
2.50
58.00 + 2.50 = 60.50
The adjusted decimals are greater than the actual decimal, so 60.50 is an overestimate.
The estimated range for the sum is from 58.00 to 60.50.
Lesson Quiz: Part 1
Estimate by rounding to the indicated place value.
3
4.5
Insert Lesson Title Here
Course 1
3-2 Estimating Decimals
1. 3.07442 + 1.352; tenths
2. 7.305 – 4.12689; nearest whole number
Lesson Quiz: Part 2
Estimate each product or quotient.
3
14
Insert Lesson Title Here
80
Course 1
3-2 Estimating Decimals
3. 6.75 1.82
4. 10.5 ÷ 3.42
5. The snowfall in December, January, and February was 18.26 cm, 29.36 cm, and 32.87 cm, respectively. About how many total centimeters of snow fell during the three months?