Measurement Conversion

Grade 5 · measurement · 100 practice problems · read aloud

🔊 Listen to this explanation

📏 Measurement Conversion

What is it and Why is it Useful?

Measurement conversion is changing a measurement from one unit to another (like inches to feet, or minutes to hours). We do this to compare sizes, follow recipes, build things, or understand distances. It's like speaking the same "measurement language"! 🗣️

How to Convert Measurements: A Step-by-Step Guide

  1. Step 1: Know the Conversion
    Memorize key equivalencies. For example: 12 inches = 1 foot.
  2. Step 2: Set Up Your Problem
    Write your measurement as a fraction over 1.
  3. Step 3: Multiply by a Magic One
    Multiply your measurement by a fraction that equals 1, using your conversion (e.g., 1 ft/12 in).
  4. Step 4: Solve
    Multiply the numbers. The old unit cancels out, leaving the new unit!

Visual Examples

Example 1: Converting a smaller unit to a larger unit
Convert 36 inches into feet.
✅ We know: 12 inches = 1 foot.
✅ Calculation: 36 in × (1 ft / 12 in) = 36/12 = 3 feet.
Answer: 3 feet

Example 2: Converting a larger unit to a smaller unit
Convert 4 feet into inches.
✅ We know: 1 foot = 12 inches.
✅ Calculation: 4 ft × (12 in / 1 ft) = 48 inches.
Answer: 48 inches

⚠️ Common Mistakes to Avoid

  • Multiplying vs. Dividing: Students often divide when they should multiply, or vice versa. Remember: When converting to a smaller unit, your number should get bigger. When converting to a larger unit, your number should get smaller.
  • Using the Wrong Conversion: Mixing up 12 inches in a foot with 3 feet in a yard. Always double-check your conversion fact!

💡 Tips & Tricks

  • King Henry Doesn't Usually Drink Chocolate Milk: This phrase helps remember the metric prefixes (Kilo-, Hecto-, Deca-, Unit, Deci-, Centi-, Milli-).
  • The "Bigger to Smaller" Rule: If you are converting a bigger unit (feet) to a smaller one (inches), multiply. If you are converting a smaller unit (inches) to a bigger one (feet), divide.
  • Draw a picture! A number line can help you visualize if your answer makes sense.

Practice Makes Perfect!

Try these ideas to get better:

  • Use a ruler or tape measure at home. Measure something in inches and then convert it to feet.
  • Practice with time: How many seconds are in 5 minutes?
  • Ask a parent to give you a "conversion challenge" during car rides, like "If I'm 60 inches tall, how many feet tall am I?"

Practice problems

6 of the 100, worked through step by step — try them before opening the answer.

1 2.5 × 3.2 = ?

Hint: When multiplying decimals, first multiply as if they were whole numbers, then count the total decimal places in the original numbers to determine where to place the decimal point in your final answer.

Show the answer

Answer: 8

  1. Write the numbers as fractions. 2.5 = 25/10 3.2 = 32/10
  2. Multiply the fractions. (25/10) × (32/10) = (25 × 32) / (10 × 10)
  3. Multiply the numerators. 25 × 32: First, 25 × 30 = 750 Then, 25 × 2 = 50 Add: 750 + 50 = 800 So numerator = 800.
  4. Multiply the denominators. 10 × 10 = 100
  5. Combine numerator and denominator. 800 / 100
  6. Simplify the fraction. 800 ÷ 100 = 8 Final answer: 8

Let's multiply 2.5 by 3.2 step by step.

2 2.5 × 4.2 = ?

Hint: When multiplying decimals, first multiply as if they were whole numbers, then count the total decimal places in both factors to determine where to place the decimal point in your answer.

Show the answer

Answer: 10.5

  1. Write the numbers without decimals. 2.5 is the same as 25/10, and 4.2 is the same as 42/10. So 2.5 × 4.2 = (25/10) × (42/10).
  2. Multiply the numerators: 25 × 42. First, 25 × 40 = 1000. Then, 25 × 2 = 50. Add: 1000 + 50 = 1050. So numerator = 1050.
  3. Multiply the denominators: 10 × 10 = 100. So we have 1050 / 100.
  4. Simplify 1050 / 100. Dividing 1050 by 100 means moving the decimal point two places to the left: 1050.0 → 10.50.
  5. Final answer: 10.5. Thus, 2.5 × 4.2 = 10.5.

Let's multiply 2.5 × 4.2 step by step.

3 3.5 × 2.4 = ?

Hint: When multiplying decimals, first multiply as if they were whole numbers, then count the total decimal places in both factors to determine where to place the decimal point in the product.

Show the answer

Answer: 8.4

  1. Write the numbers as fractions. 3.5 is the same as 35/10. 2.4 is the same as 24/10.
  2. Multiply the fractions. (35/10) × (24/10) = (35 × 24) / (10 × 10)
  3. Multiply the numerators. 35 × 24: First, 35 × 20 = 700 Then, 35 × 4 = 140 Add them: 700 + 140 = 840 So, 35 × 24 = 840.
  4. Multiply the denominators. 10 × 10 = 100.
  5. Combine numerator and denominator. We have 840 / 100.
  6. Simplify the fraction. 840 ÷ 100 = 8.40, or 8.4. Final Answer: 8.4

Let's multiply 3.5 × 2.4 step by step.

4 2.5 × 3.6 = ?

Hint: When multiplying decimals, first multiply as if they were whole numbers, then determine the correct placement of the decimal point in the final answer.

Show the answer

Answer: 9

  1. Multiply 25 × 36 25 × 36 = 900
  2. Count the total decimal places in the original numbers 2.5 has 1 decimal place 3.6 has 1 decimal place Total decimal places = 1 + 1 = 2
  3. Place the decimal point in the product 900 becomes 9.00
  4. Simplify the answer 9.00 = 9

The answer is 9.

5 3.75 × 2.4 = ?

Hint: When multiplying decimals, first multiply as if they were whole numbers, then count the total decimal places in both factors to determine where to place the decimal point in the product.

Show the answer

Answer: 9

  1. Write the numbers without decimals. 3.75 has 2 decimal places. 2.4 has 1 decimal place. So total decimal places = 2 + 1 = 3. We will first multiply 375 by 24.
  2. Multiply 375 by 20. 375 × 20 = 7500.
  3. Multiply 375 by 4. 375 × 4 = 1500.
  4. Add the results. 7500 + 1500 = 9000.
  5. Apply the decimal places. We had 3 decimal places total, so move the decimal point 3 places to the left in 9000. 9000 → 9.000
  6. Final answer. 9.000 = 9. So, 3.75 × 2.4 = 9.

Let's multiply 3.75 by 2.4 step by step.

6 2.75 × 3.6 = ?

Hint: When multiplying decimals, first multiply as if they were whole numbers, then count the total decimal places in the original numbers to place the decimal point in your final answer.

Show the answer

Answer: 9.9

  1. Multiply 2.75 × 3.6 as if they were whole numbers: 275 × 36
  2. 275 × 30 = 8,250
  3. 275 × 6 = 1,650
  4. Add the partial products: 8,250 + 1,650 = 9,900
  5. Count the decimal places: 2.75 has 2 decimal places, 3.6 has 1 decimal place, so total of 3 decimal places
  6. Place the decimal point in 9,900 to get 9.900, which simplifies to 9.9
  7. The answer is 9.9
Practise this topic — 10 free problems, no signup →