Convert Measurements

Grade 4 · measurement · 100 practice problems · read aloud

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Convert Measurements 📏

What is Converting Measurements?

Converting measurements means changing a measurement from one unit to another, like turning feet into inches or minutes into seconds. We do this to compare sizes, times, or amounts more easily. It's like knowing that 1 dollar is the same as 100 pennies!

How to Convert: Step-by-Step

  1. Know the Rule: First, you need to know the conversion rule. For example: 1 foot = 12 inches.
  2. Multiply or Divide: To convert from a LARGER unit to a SMALLER unit, you multiply. To convert from a SMALLER unit to a LARGER unit, you divide.
  3. Do the Math: Perform the multiplication or division carefully.
  4. Label Your Answer: Always write the correct unit with your number!

Examples

Example 1: Feet to Inches

How many inches are in 4 feet?

Step 1: Rule: 1 foot = 12 inches.

Step 2: Feet are larger than inches, so we multiply.

Step 3: 4 feet × 12 inches/foot = 48 inches.

Example 2: Minutes to Seconds

How many seconds are in 5 minutes?

Step 1: Rule: 1 minute = 60 seconds.

Step 2: Minutes are larger than seconds, so we multiply.

Step 3: 5 minutes × 60 seconds/minute = 300 seconds.

Common Mistakes to Avoid 🚫

  • Multiplying vs. Dividing: The biggest mix-up! Remember: Larger to Smaller = Multiply. Smaller to Larger = Divide.
  • Forgetting the Unit: An answer of "48" is wrong. It must be "48 inches."
  • Using the Wrong Rule: Don't confuse feet and inches with minutes and seconds! Always double-check your conversion rule first.

Tips & Tricks

  • King Henry Died Monday Drinking Chocolate Milk: This silly sentence helps remember metric prefixes (Kilo, Hecto, Deca, Meter, Deci, Centi, Milli).
  • Draw a Picture: If you're stuck, draw a ruler or a clock to help you visualize the problem.
  • Ask Yourself: "Should my answer be a bigger number or a smaller number?" If you are converting feet to inches, your answer should be a bigger number, so you know to multiply.

How to Practice

The best way to get better is to practice!

  • Use a ruler or tape measure at home. Measure something in feet, then convert it to inches.
  • Time yourself! How many seconds does it take to brush your teeth? Convert that to minutes.
  • Ask a friend or parent to give you quick problems: "If I have 3 quarts of juice, how many cups is that?" (Remember: 1 quart = 4 cups).

Practice problems

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

1 3.5 × 4 = ?

Hint: When multiplying a decimal by a whole number, multiply as if both were whole numbers, then place the decimal point correctly in the result.

Show the answer

Answer: 14

  1. Understand the multiplication. 3.5 × 4 means we are adding 3.5 a total of 4 times.
  2. Break 3.5 into a whole number and a decimal. 3.5 is the same as 3 + 0.5.
  3. Multiply each part by 4. First, multiply the whole number part: 3 × 4 = 12. Next, multiply the decimal part: 0.5 × 4 = 2.
  4. Add the results together. 12 + 2 = 14.
  5. Final answer. So, 3.5 × 4 = 14.

Let's solve 3.5 × 4 step by step.

2 2.5 × 4 = ?

Hint: When multiplying a decimal by a whole number, first multiply as if both were whole numbers, then place the decimal point in the correct position based on the original decimal.

Show the answer

Answer: 10

  1. Understand the problem. We are multiplying 2.5 by 4. This means we are adding the number 2.5 a total of 4 times.
  2. Set up the multiplication. We write the problem as: 2.5 × 4
  3. Consider the decimal. The number 2.5 is the same as the fraction 25/10, or 25 tenths. Multiplying 25 tenths by 4 is easier to think about.
  4. Perform the multiplication without the decimal first. Ignore the decimal point for a moment and multiply the numbers as if they were whole numbers. 25 × 4 = 100
  5. Reintroduce the decimal point. Since we originally had one digit after the decimal point in the number 2.5, our answer must also have one digit after the decimal point. So, 100 becomes 100.0, but we can simply write this as 100.
  6. Verify the result. We can check by adding 2.5 four times: 2.5 + 2.5 = 5.0 5.0 + 2.5 = 7.5 7.5 + 2.5 = 10.0 This confirms our result.
  7. Final Answer. The product of 2.5 and 4 is 10.

3 3.75 × 4 = ?

Hint: When multiplying a decimal by a whole number, multiply as if both were whole numbers, then place the decimal point correctly in your answer.

Show the answer

Answer: 15

  1. Understand the number 3.75 3.75 is the same as 3 + 0.75, or 3 + 3/4.
  2. Multiply 3.75 by 4 using the distributive property 3.75 × 4 = (3 + 0.75) × 4 = (3 × 4) + (0.75 × 4)
  3. Calculate 3 × 4 3 × 4 = 12
  4. Calculate 0.75 × 4 0.75 means 75/100, which simplifies to 3/4. So 0.75 × 4 = (3/4) × 4 = (3 × 4) / 4 = 12 / 4 = 3.
  5. Add the two results 12 + 3 = 15 Therefore, 3.75 × 4 = 15.

Let's multiply 3.75 × 4 step by step.

4 3.25 × 8 = ?

Hint: Think about how to multiply a decimal by a whole number. You can break the decimal into parts to make it easier.

Show the answer

Answer: 26

  1. Write the multiplication: 3.25 × 8
  2. Multiply 3.25 by 8. First, multiply the whole number part: 3 × 8 = 24
  3. Multiply the decimal part: 0.25 × 8 = 2
  4. Add the two results together: 24 + 2 = 26
  5. The final answer is 26.

5 3.5 × 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 the product.

Show the answer

Answer: 14.7

  1. Write the numbers without decimals. 3.5 is the same as 35/10, and 4.2 is the same as 42/10. So 3.5 × 4.2 = (35/10) × (42/10).
  2. Multiply the numerators: 35 × 42. First, 35 × 40 = 1400. Then, 35 × 2 = 70. Add: 1400 + 70 = 1470. So 35 × 42 = 1470.
  3. Multiply the denominators: 10 × 10 = 100. So (35/10) × (42/10) = 1470/100.
  4. Simplify 1470/100. Dividing by 100 moves the decimal point two places to the left: 1470 → 14.70.
  5. Remove the trailing zero if needed: 14.70 = 14.7. Final answer: 14.7

Let's multiply 3.5 × 4.2 step by step.

6 2.5 × 4.8 = ?

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 correctly in your answer.

Show the answer

Answer: 12

  1. Multiply the numbers as if they were whole numbers: 25 × 48
  2. 25 × 40 = 1000
  3. 25 × 8 = 200
  4. 1000 + 200 = 1200
  5. Count the decimal places in the original numbers: 2.5 has 1 decimal place, 4.8 has 1 decimal place, so total decimal places = 1 + 1 = 2
  6. Place the decimal point in 1200 to have 2 decimal places: 12.00
  7. 12.00 simplifies to 12

The answer is 12.

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