Two crayons are placed on a table. The red one starts at the edge of the table, and the blue one starts a few inches from the edge. The blue one's tip reaches further than the red one's tip. Which crayon is definitely longer?
AThe blue crayon, because its tip reaches further
BThe red crayon, because it starts closer to the edge
CYou can't tell — they need to be lined up at the same starting point
DThey are the same length, because they are both on the table
To compare lengths fairly, both objects must start from the same point. If they start at different places, the one whose tip reaches further might actually be shorter. The blue crayon's tip reaching further only tells us where it ends, not how long it is. When you line them up from the same starting point, then you can compare accurately.
Question 2 Multiple Choice
You want to compare the length of your bedroom door to the length of your living room sofa, but you can't move either one. What can you use to compare them?
AYou can only compare them if you move one next to the other
BA piece of string cut to match one object, then compared to the other
CYour hands, by counting how many times they fit along each object
DYou cannot compare them at all
When two objects cannot be placed side by side, you can use a third object — like a piece of string — to help. Stretch the string along one object, mark or cut it to that length, then take the string to the other object. This is called indirect comparison. The string acts as a messenger, carrying length information from one object to the other.
Question 3 True / False
Two sticks are exactly the same length if, when you line up their starting ends, their other ends also line up perfectly.
TTrue
FFalse
Answer: True
When both sticks start from the same point and end at the same point, there is no difference in length — they are the same length. The alignment of starting points is essential to make this comparison fair. If they start at the same place and end at the same place, they must be identical in length.
Question 4 True / False
The crayon whose tip sticks out the furthest is generally the longest.
TTrue
FFalse
Answer: False
This is only true if both crayons start from the same point. If one crayon starts further back, its tip might reach further even though it is actually shorter. A fair comparison requires both objects to start at the same place. Without aligned starting points, the tip position alone tells you nothing reliable about which is longer.
Question 5 Short Answer
Why is it important to line up the starting ends of two objects when comparing their lengths?
Think about your answer, then reveal below.
Model answer: If the starting points are not aligned, you are not comparing the full lengths of both objects — you might be giving one object a head start. Only when both start from the same point can you tell whether one reaches further because it is actually longer.
Length is measured from start to end. If one object starts further along, its end will appear further even if it is the same or shorter length. Lining up starting points removes this unfair advantage and lets you directly compare the full extent of each object.