Measure Length With a Ruler

Measure Length with a Ruler

1. Identify the starting point
   Place the ruler so the object’s left end or starting mark lines up with 0. Measuring from 0 avoids extra subtraction.

2. Read the ending point carefully
   Look straight down at the mark where the object ends. The number at that mark gives the length, along with the ruler’s unit.

3. Use the correct unit
   If the ruler shows inches, write the answer in inches; if it shows centimeters, write the answer in centimeters. Keep the unit in the final answer.

4. Simplify the answer if needed
   If the result is a fraction, reduce it when possible. For example, write an equivalent simpler fraction if the answer is not already in lowest terms.

Check your work

• Make sure the ruler started at 0.
• Make sure you read the mark at the end of the object, not the line before or after it.
• Confirm the final answer is written with the correct unit and is simplified.

If the object does not start at 0, measure the distance between the two marks by subtracting the starting reading from the ending reading.