Addition and subtraction with Decimals

5th grade math Unit #2

Unit 2

Big Idea 1: Read and Write Whole Numbers and Decimals

2.1 Decimals as Equal Divisions

2.2 Thousands to Thousandths

2.3 Equate and Compare Thousandths

Big Idea 2: Addition and Subtraction

2.4 Adding and Subtracting Decimals

2.5 Add Whole Numbers and Decimals

2.6 Subtract Whole and Decimal Numbers

2.7 Properties and Strategies

Big Idea 3: Round and Estimate with Decimals

2.8 Round and Estimate with Decimals

2.9 Graph with Decimal Numbers

2.1

Lesson 2.1

Decimals as Equal Divisions

Objective: We will understand decimals as equal divisions of a whole.

Vocabulary:

Math Talk Question (Solve, Explain, Questions, Justify):

Sally has a dime, a nickel, and three pennies. What fraction would represent the amout of money that she has? What decimal would represent the amount of money that she has?

Decimal: a number that includes a decimal point separating the whole number part of the number from the fraction part of the number.

Tenth: a unit fraction representing one of ten equal parts of a whole, written as 0.1 or 1/10.

Hundredth: a unit fraction representing one of one hundred equal parts of a whole, written as 0.01 or 1/100

Thousandth: 0.001 or 1/1000

2.2

Lesson 2.2

Thousands to Thousanths

Math Talk Question (Solve, Explain, Questions, Justify):

Ty needs $115 for a trip. He has $25 saved. To earn the rest, Ty works 3 hours per day 3 days per week. He recieved a $2 an hour raise and now he earns $8 an hour. For taxes, $5 per day is subtracted from his earnings. If Ty works for one week, how many more days must he work to earn the money?

Objective: We will read, write, and model whole and decimal numbers.

Vocabulary:

Standard Form: 35.026

Word Form: Thirty-five and twenty-six thousandths

Expanded Form: 30 + 5 + 0.026

Power of Ten: (3 x 10) + (5 x 1) + (2 x 0.01) + (6 x 0.001)

2.3

Lesson 2.3

Equate and Compare Thousandths

Math Talk Question (Solve, Explain, Questions, Justify):

Tyra and Kyle bought packages of paper plates. Each package had the same number of plates. Tyra bought a total of 32 plates and Kyle bought a total of 56 plates. How many paper plates could have been in each package. Explain hour your found your answer.

Objective: We will model and identify equivalent decimals.

Vocabulary:

Equivalent Decimal: Decmials that represent the same value.

Practice:

0.5 ___ 0.500 _ 0.50 ___ 0.05

0.17 _____ 0.9

73 _____ 138

Objective: We will model and identify equivalent decimals.

Vocabulary:

Equivalent Decimal: Decmials that represent the same value.

Practice:

0.5 ___ 0.500 _ 0.50 ___ 0.05

0.17 _____ 0.9

73 _____ 138

2.4

Lesson 2.4

Adding and Subracting Decimals

Math Talk Question (Solve, Explain, Questions, Justify):

A rectangle has a perimeter of 10 cm and an area of 6 sq cm. If the length and width triple in length, will the perimeter also triple? Use the rectangle's dimensions to show your answer is correct.

Objective: We will model adding and subtracting decimals.

Practice:

0.5 ___ 0.500 _ 0.50 ___ 0.05

0.17 _____ 0.9

73 _____ 138

2.5

Lesson 2.5

Add Whole Numbers and Decimals

Math Talk Question (Solve, Explain, Questions, Justify):

Tyra and Kyle bought packages of paper plates. Each package had the same number of plates. Tyra bought a total of 32 plates and Kyle bought a total of 56 plates. How many paper plates could have been in each package. Explain hour your found your answer.

Objective: We will model and identify equivalent decimals.

Vocabulary:

Equivalent Decimal: Decmials that represent the same value.

Practice:

0.5 ___ 0.500 _ 0.50 ___ 0.05

0.17 _____ 0.9

73 _____ 138

Lesson 2.5

Add Whole Numbers and Decimals

Math Talk Question (Solve, Explain, Questions, Justify):

Follow all the steps carefully: Start with the number 53,017.682 and increase the number by 0.07. Next decrease the number by 1,000 and add an 8 in the hundreds place. Now subtract 2 from the tenths place.

Objective: We will add whole numbers and decimals to hundredths.

Practice:

0.9 + 0.06 = ____

0.47 + 0.25 = ____

6.07 - 4 = ____

2.6

Lesson 2.6

Subtract Whole Numbers and Decimals

Math Talk Question (Solve, Explain, Questions, Justify):

Adam wanted to place a fence around his garden that measures 7.3 yards long and 2.5 yards wide. He found the perimeter to be 1.96 yards. He knows this amount must be incorrect. What happened? Give the correct perimeter.

Objective: We will subtract whole and decimal numbers to hundredths.

Lesson 2.7

Properties of Addition

Math Talk Question (Solve, Explain, Questions, Justify):

Each student needs 5 inches of string . Paul and Mari did not have any. The teacher gave Paul 1/4 of the string from the school supply closet. Then Paul gave 1/2 of this to Mari. Mari had just enough string. How much string is left in the school supply closet?

Objective: We will subtract whole and decimal numbers to hundredths. use the commutative, associative, and distributive properties to compute mentally.

Practice:

Commutative Property: a + b = b + a

Associative Property: (a + b) + c = a + (b + c)

Distributive Property: a x (b + c) = (a x b) + (b x c)

Lesson 2.8

Round and Estimate With Decimals

Lesson 2.9

Graph with Decimal Numbers

Math Talk Question (Solve, Explain, Questions, Justify):

Tara earned twice as many points as Jerome. Jerome's points are exactly three times more than Wylie's points. Altogether they have 40 points. How many points does each person have?

Objective: We will read and construct graphs with decimal scales and decimal numbers.

Addition and subtraction with Decimals

5th grade math Unit #2

Unit 2

Big Idea 1: Read and Write Whole Numbers and Decimals

Big Idea 2: Addition and Subtraction

Big Idea 3: Round and Estimate with Decimals

Lesson 2.1

Decimals as Equal Divisions

Objective: We will understand decimals as equal divisions of a whole.

Vocabulary:

Math Talk Question (Solve, Explain, Questions, Justify):

Sally has a dime, a nickel, and three pennies. What fraction would represent the amout of money that she has? What decimal would represent the amount of money that she has?

Decimal: a number that includes a decimal point separating the whole number part of the number from the fraction part of the number.

​

Tenth: a unit fraction representing one of ten equal parts of a whole, written as 0.1 or 1/10.

​

Hundredth: a unit fraction representing one of one hundred equal parts of a whole, written as 0.01 or 1/100

​

Thousandth: 0.001 or 1/1000

​

Lesson 2.2

Thousands to Thousanths

Math Talk Question (Solve, Explain, Questions, Justify):

Ty needs $115 for a trip. He has $25 saved. To earn the rest, Ty works 3 hours per day 3 days per week. He recieved a $2 an hour raise and now he earns $8 an hour. For taxes, $5 per day is subtracted from his earnings. If Ty works for one week, how many more days must he work to earn the money?

Objective: We will read, write, and model whole and decimal numbers.

Vocabulary:

Standard Form: 35.026

​

Word Form: Thirty-five and twenty-six thousandths

​

Expanded Form: 30 + 5 + 0.026

​

Power of Ten: (3 x 10) + (5 x 1) + (2 x 0.01) + (6 x 0.001)

​

​

Lesson 2.3

Equate and Compare Thousandths

Math Talk Question (Solve, Explain, Questions, Justify):

Tyra and Kyle bought packages of paper plates. Each package had the same number of plates. Tyra bought a total of 32 plates and Kyle bought a total of 56 plates. How many paper plates could have been in each package. Explain hour your found your answer.

Objective: We will model and identify equivalent decimals.

Vocabulary:

Equivalent Decimal: Decmials that represent the same value.

​

​

Practice:

0.5 _____ 0.500 _____ 0.50 _____ 0.05

​

0.17 _____ 0.9

​

73 _____ 138

Objective: We will model and identify equivalent decimals.

Vocabulary:

Equivalent Decimal: Decmials that represent the same value.

​

​

Practice:

0.5 _____ 0.500 _____ 0.50 _____ 0.05

​

0.17 _____ 0.9

​

73 _____ 138

Lesson 2.4

Adding and Subracting Decimals

Math Talk Question (Solve, Explain, Questions, Justify):

A rectangle has a perimeter of 10 cm and an area of 6 sq cm. If the length and width triple in length, will the perimeter also triple? Use the rectangle's dimensions to show your answer is correct.

Objective: We will model adding and subtracting decimals.

Practice:

0.5 _____ 0.500 _____ 0.50 _____ 0.05

​

0.17 _____ 0.9

​

73 _____ 138

Lesson 2.5

Add Whole Numbers and Decimals

Math Talk Question (Solve, Explain, Questions, Justify):

Tyra and Kyle bought packages of paper plates. Each package had the same number of plates. Tyra bought a total of 32 plates and Kyle bought a total of 56 plates. How many paper plates could have been in each package. Explain hour your found your answer.

Objective: We will model and identify equivalent decimals.

Vocabulary:

Equivalent Decimal: Decmials that represent the same value.

​

0.5 ___ 0.500 _ 0.50 ___ 0.05

0.5 ___ 0.500 _ 0.50 ___ 0.05

0.5 ___ 0.500 _ 0.50 ___ 0.05

0.5 ___ 0.500 _ 0.50 ___ 0.05