Learning Goal: Add, subtract, multiply, and divide decimals using place value and careful point placement.
Vocabulary
decimal pointThe dot that separates whole numbers from parts of a whole.
place valueThe value of a digit based on its position, like tenths or hundredths.
productThe answer when you multiply.
quotientThe answer when you divide.
What You Need to Know
To add or subtract, line up the decimal points and fill empty spots with zeros.
To multiply, ignore the points first, then count total decimal places in both factors.
To divide by a decimal, move both points right until the divisor is a whole number.
Bring the decimal point straight up into the quotient when doing long division.
Estimate first so a misplaced point is easy to catch.
Money problems usually round to two decimal places (the cents).
Worked Example I Do — watch how it works
Multiply 3.6 × 0.4.
Step 1. Multiply without points: 36 × 4 = 144.
Step 2. Count decimal places: 3.6 has 1 and 0.4 has 1, so 2 total.
Step 3. Place the point 2 spots from the right: 1.44.
Answer: 1.44
Guided Practice We Do — try it together
1. 4.7 + 2.85
💡 Hint: Line up points and write 4.70.
2. Find 15.75 − 8.90.
💡 Hint: Align the decimal points before subtracting.
3. 7.5 ÷ 0.25
💡 Hint: Move both points 2 places: 750 ÷ 25.
Independent Practice You Do — show your work
1. 8.3 − 5.76
2. 2.4 × 1.5
3. 9.6 ÷ 0.8
4. 45.6 + 7.89
5. Find 12.6 ÷ 0.6.
MCAP-Style Practice
Directions: Answer each item the way you would on the MCAP. For selected-response items, fill in the circle (○) next to the correct answer. For constructed-response items, enter your answer and show your work. Every item below assesses standard 6.NS.B.3.
Item 1Selected Response6.NS.B.3
Maria pays for lunch with a $20 bill. Her meal costs $15.75. How much change does she get?
Select the correct answer.
Item 2Selected Response6.NS.B.3
What is 7.5 ÷ 0.25?
Select the correct answer.
Item 3Constructed Response6.NS.B.3
A bottle holds 2.4 L and a cup holds 1.5 L. How many liters do they hold together?
Enter your answer in the space provided. Show your work.
Enter your answer:
Teacher Answer Key (click to show)
Independent 1
2.54
Independent 2
3.6
Independent 3
12
Independent 4
53.49
Independent 5
21
Item 1 · 6.NS.B.3
A — 20.00 − 15.75 = 4.25, so her change is $4.25.
Item 2 · 6.NS.B.3
C — Move both points two places: 750 ÷ 25 = 30.
Item 3 · 6.NS.B.3
3.9 L — Line up points: 2.4 + 1.5 = 3.9 liters.
Neft Teacher · Grade 6 MCAP Mathematics Review · Standard 6.NS.B.3