Decimal Division: Divide the total cost by the number of items to find the unit cost
- Identify the total cost: $4.50
- Identify the number of items: 3 notebooks
- Divide total cost by number of items: $4.50 ÷ 3
$4.50 ÷ 3
4 ÷ 3 = 1 remainder 1
150 cents ÷ 3 = 50 cents
1 dollar + 50 cents = $1.50
Each notebook cost $1.50
• Unit Cost: Divide total cost by number of items
• Decimal Division: Place decimal point in quotient directly above dividend
• Verification: Multiply quotient by divisor to check answer
Equal Partitioning: Divide the total length by the number of pieces to find length of each piece
12.6 ÷ 3
12 ÷ 3 = 4
0.6 ÷ 3 = 0.2
4 + 0.2 = 4.2 inches
Each piece is 4.2 inches long
• Equal Partitioning: Divide total by number of equal parts
• Decimal Division: Align decimal point in quotient with dividend
• Verification: Multiply quotient by divisor to check answer
Unit Rate: Divide the total amount by the number of units to find the rate per unit
$15.75 ÷ 5
15 ÷ 5 = 3
75 cents ÷ 5 = 15 cents
3 dollars + 15 cents = $3.15
Alex earned $3.15 per hour
• Unit Rate: Divide total by number of units to find per-unit amount
• Decimal Division: Place decimal point in quotient directly above dividend
• Verification: Multiply hourly rate by hours worked to check
Equal Sharing: Divide the total weight by the number of people to find individual share
2.4 ÷ 4
24 tenths ÷ 4 = 6 tenths
6 tenths = 0.6 kg
Each person gets 0.6 kg of flour
• Equal Sharing: Divide total by number of recipients
• Decimal Division: When dividend is smaller than divisor, result is less than 1
• Verification: Multiply individual share by number of people to check
Rate Calculation: Divide total distance by total fuel to find miles per gallon
187.5 ÷ 7.5
(187.5 × 10) ÷ (7.5 × 10) = 1875 ÷ 75
1875 ÷ 75 = 25
The car gets 25 miles per gallon
• Rate Calculation: Divide total distance by total fuel to find rate
• Decimal Division: Multiply both numbers by 10 to eliminate decimal
• Verification: Multiply rate by fuel to check distance
Equal Distribution: Divide the total volume by the number of containers to find volume per container
4.8 ÷ 6
48 tenths ÷ 6 = 8 tenths
8 tenths = 0.8 L
Each glass contains 0.8 liters of juice
• Equal Distribution: Divide total volume by number of containers
• Decimal Division: When dividend is smaller than divisor, result is less than 1
• Verification: Multiply per-glass amount by number of glasses to check
Periodic Rate: Divide the total amount by the number of periods to find the amount per period
$31.20 ÷ 8
31 ÷ 8 = 3 remainder 7
720 cents ÷ 8 = 90 cents
3 dollars + 90 cents = $3.90
Maya saved $3.90 per week
• Periodic Rate: Divide total amount by number of periods
• Decimal Division: Place decimal point in quotient directly above dividend
• Verification: Multiply weekly amount by number of weeks to check
Measurement Division: Divide the total length by the length of each piece to find the number of pieces
15.6 ÷ 1.2
(15.6 × 10) ÷ (1.2 × 10) = 156 ÷ 12
156 ÷ 12 = 13
13 pieces can be made
• Measurement Division: Divide total length by length of each piece
• Decimal Division: Multiply both numbers by 10 to eliminate decimal
• Verification: Multiply number of pieces by length of each to check
Count Division: Divide the total weight by the weight of each item to find the number of items
3.6 ÷ 0.3
(3.6 × 10) ÷ (0.3 × 10) = 36 ÷ 3
36 ÷ 3 = 12
There are 12 apples in the bag
• Count Division: Divide total weight by weight of each item
• Decimal Division: Multiply both numbers by 10 to eliminate decimal
• Verification: Multiply number of apples by weight of each to check
Equal Allocation: Divide the total budget by the number of recipients to find per-person allocation
$24.00 ÷ 5
24 ÷ 5 = 4 remainder 4
400 cents ÷ 5 = 80 cents
4 dollars + 80 cents = $4.80
Sarah can spend $4.80 per gift
• Equal Allocation: Divide total budget by number of recipients
• Decimal Division: Place decimal point in quotient directly above dividend
• Verification: Multiply per-gift amount by number of gifts to check
Decimal Division Guide
• Place decimal point in quotient directly above dividend
• When divisor has decimals, multiply both by 10, 100, etc.
• Divide as with whole numbers
• Add zeros to dividend if needed
• If divisor has 1 decimal place, multiply both by 10
• If divisor has 2 decimal places, multiply both by 100
• If divisor has 3 decimal places, multiply both by 1000
• Dividend and divisor must be multiplied by same number
• Forgetting to place decimal point in quotient
• Only multiplying divisor by 10, not dividend
• Placing decimal point incorrectly
• Not checking reasonableness of answer
• Always place decimal point in quotient first
• When divisor has decimals, eliminate them by multiplying both
• Estimate first to check reasonableness
• Verify by multiplying quotient by divisor
12.6 ÷ 3 = 4.2
7.5 ÷ 0.5 = 15
3.6 ÷ 0.4 = 9
Dividend: The number being divided
Divisor: The number that divides the dividend
Quotient: The result of the division
Unit Rate: A rate with denominator of 1, expressing quantity per single unit
Equal Partitioning: Dividing a quantity into equal parts
- Identify: Determine which number is the dividend and which is the divisor
- Eliminate decimals: If divisor has decimals, multiply both numbers by 10, 100, etc.
- Place decimal: Put decimal point in quotient directly above dividend
- Divide: Perform division as with whole numbers
- Verify: Multiply quotient by divisor to check your answer
• Decimal Placement: Place decimal point in quotient directly above dividend's decimal point
• Decimal Elimination: Multiply both numbers by 10, 100, or 1000 to eliminate divisor decimals
• Verification: Multiply quotient by divisor to check your answer
• Estimation: Round to estimate and verify your answer
• Reasonableness: Check that your answer makes sense in the context of the problem
Decimal Division Summary
Dividend: The number being divided
Divisor: The number that divides the dividend
Quotient: The result of the division
Unit Rate: A rate with denominator of 1, expressing quantity per single unit
Equal Partitioning: Dividing a quantity into equal parts
• Always place decimal point in quotient directly above dividend's decimal point
• When divisor has decimals, multiply both numbers by 10, 100, or 1000 to eliminate decimals
• When dividend is smaller than divisor, result is less than 1
• The quotient represents how many times the divisor fits into the dividend
• Verify by multiplying quotient by divisor to get original dividend
1. Identify: Determine dividend and divisor in the problem
2. Eliminate Decimals: If divisor has decimals, multiply both by 10, 100, or 1000
3. Place Decimal: Put decimal point in quotient directly above dividend
4. Divide: Perform division as with whole numbers
5. Verify: Multiply quotient by divisor to check your answer
Simple Division: 4.8 ÷ 2 = 2.4
With Decimals: 7.5 ÷ 0.5 = 15 (multiply both by 10: 75 ÷ 5 = 15)
Unit Rate: $15.75 ÷ 5 hours = $3.15 per hour
Partitioning: 12.6 inches ÷ 3 pieces = 4.2 inches per piece
Real-world: 187.5 miles ÷ 7.5 gallons = 25 miles per gallon
• Place the decimal point in the quotient first
• When divisor has decimals, eliminate them by multiplying both numbers
• Estimate first to check reasonableness
• Remember: smaller ÷ larger = result less than 1
• Always verify by multiplying quotient by divisor
• "Decimal point in quotient goes directly above dividend's decimal point"
• "To eliminate decimals, multiply both numbers by the same power of 10"
• "Dividend ÷ Divisor = Quotient (the answer)"
• "Check by multiplying: Quotient × Divisor = Dividend"
• "If dividend is smaller than divisor, answer is less than 1"
Questions & Answers
Question: I always get confused about where to put the decimal point when dividing decimals. Any tips?
Answer: Great question! Here's a foolproof method for decimal placement in division:
- Place the decimal point first: Put the decimal point in the quotient directly above the dividend's decimal point
- Eliminate decimals in divisor: If the divisor has decimals, multiply both numbers by 10, 100, or 1000 to make the divisor a whole number
- Divide as usual: Perform the division with the decimal point already in place
Example: For 4.8 ÷ 2
1. Place decimal point: 4.8 ÷ 2 = _._
2. Divide: 4 ÷ 2 = 2, 8 ÷ 2 = 4
3. Result: 2.4
The key is putting the decimal point in the quotient BEFORE you start dividing!
Question: How can I help my child practice decimal division at home?
Answer: Real-world contexts make decimal division meaningful! Try these activities:
- Shopping: Calculate unit prices (cost per item, per pound, per liter)
- Cooking: Divide recipes, measure ingredients equally among servings
- Travel: Calculate miles per gallon, average speed, or distance per day
- Budgeting: Divide allowance or earnings into equal parts
Also practice with problems that involve sharing or partitioning: "If 3 friends share $7.50 equally, how much does each get?"
Start with simple problems and gradually increase complexity as skills develop.
Question: What do I do when the divisor has decimals? It confuses me!
Answer: When the divisor has decimals, eliminate them by multiplying both numbers by the same power of 10! Here's the method:
- Count decimal places in divisor: How many digits after the decimal point?
- Multiply both numbers by 10, 100, or 1000: Based on the count from step 1
- Divide as normal: With a whole number divisor
- Place decimal point: In quotient directly above where it appears in the new dividend
Example: 7.5 ÷ 0.5
Divisor has 1 decimal place, so multiply both by 10:
(7.5 × 10) ÷ (0.5 × 10) = 75 ÷ 5 = 15
This method turns any decimal division into whole number division!