Grade 6 Mathematics · Unit 2: Understanding the World Around Us Through StatisticsStandard 6.NOS.3

Lesson 2.12Multiply Decimals

Set B · Version ASecond form · supported practice

Mastery check☐ Exceeds☐ Meets target☐ Needs practice
Name Date Period

Learning target I can multiply decimals and place the decimal point correctly in the product.

Why This Matters The station needs 4.5 meters of heat shielding that costs $12.60 per meter. Commander Diaz needs to calculate the total cost before submitting the supply order. What is the total cost of the shielding?

RememberMultiply Decimals

Multiplying Decimals To multiply decimals, you multiply the numbers as if there were no decimal points. Then you count the decimal places and put the point back in the answer.

  1. Multiply the numbers as if they were whole numbers (ignore decimals during multiplication).
  2. Count the total number of decimal places in both factors.
  3. Place the decimal point in the product so it has that same total number of decimal places

Words: Product (Producto)Decimal point (Punto decimal)Estimate (Estimar)Place value (Valor posicional)Decimal places (Cifras decimales)

Part 1Practice the skillshow every step
  1. 1Circle the letter of the best answer. Show how you know.

    What is 3.2 + 4.5?

    1. A7.5
    2. B7.7
    3. C8.7
    4. D77
    Line up the place values
    1. 1Line upPoints under points.
    2. 2Fill gapsWrite in the zeros.
    3. 3OperateRight to left.
    4. 4Bring the point downStraight down.
  2. 2Circle the letter of the best answer. Show how you know.

    What is 14.6 + 3.85?

    1. A17.45
    2. B18.35
    3. C18.45
    4. D18.55
    Line up the place values
    1. 1Line upPoints under points.
    2. 2Fill gapsWrite in the zeros.
    3. 3OperateRight to left.
    4. 4Bring the point downStraight down.
Part 2Apply itreal-world problems
  1. 3Circle the letter of the best answer. Show how you know.

    What is 20.3 − 7.48?

    1. A12.18
    2. B12.82
    3. C12.92
    4. D13.82
    Line up the place values
    1. 1Line upPoints under points.
    2. 2Fill gapsWrite in the zeros.
    3. 3OperateRight to left.
    4. 4Bring the point downStraight down.
  2. 4Circle the letter of the best answer. Show how you know.

    What is 50 − 23.47?

    1. A26.53
    2. B26.63
    3. C27.47
    4. D27.53
    Line up the place values
    1. 1Line upPoints under points.
    2. 2Fill gapsWrite in the zeros.
    3. 3OperateRight to left.
    4. 4Bring the point downStraight down.
  3. 5Circle the letter of the best answer. Show how you know.

    A family is buying 3.5 pounds of deli meat that costs $6.80 per pound at the grocery store. 3.5 × $6.80 = ?

    1. A$2.38
    2. B$21.80
    3. C$23.80
    4. D$238.00
    per 1
    1. 1LabelWrite what each column is.
    2. 2Find per 1Divide to get one.
    3. 3ScaleMultiply up to what is asked.
    4. 4CheckDoes the size make sense?
  4. 6Circle the letter of the best answer. Show how you know.

    A family is buying 3.5 pounds of deli meat that costs $6.80 per pound at the grocery store. Round to estimate: about how much should the deli meat cost?

    1. Aabout $2.80
    2. Babout $14
    3. Cabout $28
    4. Dabout $280
    Show your work

Explain your thinkingHow did estimating by rounding help you sort the products? How do you decide where to place the decimal in the exact product?

Sentence starter I estimated ___ x ___ by rounding to ___ x ___ = ___, which told me the product is ___ than 20.

3-Point Exit Checklist: ☐ 1. Units & Labels Verified ☐ 2. Mathematical Reasoning Stated ☐ 3. Calculations Double-Checked
How did it go? ☐ 4 · I can teach it☐ 3 · I've got it☐ 2 · I need a hint☐ 1 · I need help
Grade 6 Mathematics · Unit 2: Understanding the World Around Us Through StatisticsStandard 6.NOS.3

Lesson 2.12Multiply Decimals

Set B · Version BSecond form · core practice

Mastery check☐ Exceeds☐ Meets target☐ Needs practice
Name Date Period

Learning target I can multiply decimals and place the decimal point correctly in the product.

Why This Matters The station needs 4.5 meters of heat shielding that costs $12.60 per meter. Commander Diaz needs to calculate the total cost before submitting the supply order. What is the total cost of the shielding?

Part 1Understand the ideamodels and meaning
  1. 1Write the letter of the matching item on each line.

    Match each food truck order to its total.

    1. 4 × $3.75 (combo meals)
    2. 5 × $1.80 (sodas)
    3. 3 × $2.40 (cookies)
    4. 7 × $4.20 (burritos)
    5. 0.5 × $0.80 (napkin pack)
    • A$15.00
    • B$9.00
    • C$7.20
    • D$29.40
    • E$0.40
Part 2Apply itreal-world problems
  1. 2Circle the letter of the best answer. Show how you know.

    A family is buying 3.5 pounds of deli meat that costs $6.80 per pound at the grocery store. A student answered $238.00. What went wrong?

    1. AThey added instead of multiplying
    2. BThey rounded too early
    3. CThey used the wrong price
    4. DThey put the decimal point in the wrong place
    Show your work
  2. 3Circle the letter of the best answer. Show how you know.

    A customer orders 3 taco baskets at $4.25 each. What is the total before tax?

    1. A$1.275
    2. B$12.15
    3. C$12.75
    4. D$127.50
    Show your work
  3. 4Circle the letter of the best answer. Show how you know.

    Each lemonade uses 0.6 of a cup of sugar, and sugar costs $0.40 per cup. How much sugar cost is in one lemonade? (0.6 × 0.4)

    1. A$0.024
    2. B$0.24
    3. C$2.40
    4. D$24.00
    per 1
  4. 5Circle the letter of the best answer. Show how you know.

    The truck sells 2.5 pounds of fries, and each pound earns $1.20 in profit. What is the total profit? (2.5 × 1.2)

    1. A$0.30
    2. B$3.00
    3. C$3.70
    4. D$30.00
    Show each partial product, then add them
Part 3Explain and correctreasoning
  1. 6Find the mistake. Explain it, then show the correct work.

    Level 2 Extension — Find the Cashier's Mistake

    1. 1Order2 burrito bowls at $6.45 each: 2 × 6.45
    2. 2Multiply as whole numbers2 × 645 = 1,290
    3. 3Count decimal places6.45 has 2 decimal places → 2 total
    4. 4Place the decimal point129.0, so the total is $129.00

    Which step has the mistake? Explain what went wrong, then show the correct work.

    Correct work
    Correct answer:

Explain your thinkingHow did estimating by rounding help you sort the products? How do you decide where to place the decimal in the exact product?

3-Point Exit Checklist: ☐ 1. Units & Labels Verified ☐ 2. Mathematical Reasoning Stated ☐ 3. Calculations Double-Checked
How did it go? ☐ 4 · I can teach it☐ 3 · I've got it☐ 2 · I need a hint☐ 1 · I need help