Ordering Three Objects by Length

Learn how to line up three things from shortest to longest (or longest to shortest) by comparing how long each one is.

Reading is good — doing is better. Practice Ordering Three Objects by Length as an interactive lesson.

Definition

Ordering three objects by length means looking at three things, deciding how long each one is, and then putting them in order — either starting with the shortest and ending with the longest, or starting with the longest and ending with the shortest.

Remember the rule

Line them up at the same starting point, then look at where each one ends — the one that ends first is shortest, the one that ends last is longest, and the one in the middle is in between!

Key words

length: How long something is from one end to the other end.
shortest: The object that is the least long — it takes up the smallest amount of space from end to end.
longest: The object that is the most long — it takes up the biggest amount of space from end to end.
order: Arranging things so they go in a pattern, like from smallest to biggest.
compare: Looking at two or more things to see how they are the same or different in size.
middle: The object that is not the shortest and not the longest — it falls in between the other two.
shorter than: When one object is less long than another object.
longer than: When one object is more long than another object.

Worked examples

A red crayon is 3 inches long, a blue crayon is 5 inches long, and a green crayon is 1 inch long. Put them in order from shortest to longest.

→ Green crayon (1 inch), red crayon (3 inches), blue crayon (5 inches). · Start with the smallest number — 1 is less than 3, and 3 is less than 5.

A pencil is 7 inches, a paper clip is 2 inches, and a marker is 5 inches. Order them from longest to shortest.

→ Pencil (7 inches), marker (5 inches), paper clip (2 inches). · This time start with the biggest number and count down.

Three sticks are lying on a table. Stick A ends at the 4-inch mark, Stick B ends at the 6-inch mark, and Stick C ends at the 2-inch mark. All sticks start at the same spot. Order them from shortest to longest.

→ Stick C, Stick A, Stick B. · When all objects start at the same end, the one that reaches the farthest is the longest.

A ribbon, a shoelace, and a belt are laid flat. The ribbon is shorter than the shoelace. The belt is longer than the shoelace. Which order goes from shortest to longest?

→ Ribbon, shoelace, belt. · You can use clue words like 'shorter than' and 'longer than' even without numbers.

Three friends cut pieces of yarn. Ana's piece is 8 inches, Ben's piece is 8 inches, and Carl's piece is 3 inches. Order them from shortest to longest.

→ Carl (3 inches), Ana (8 inches), Ben (8 inches). · Two objects can be the same length — they both share the longest spot.

A fork, a spoon, and a knife are on a table. The spoon is the shortest, the knife is the longest, and the fork is in the middle. Write the order from longest to shortest.

→ Knife, fork, spoon. · Finding the middle object is the key step — it is always the one that is left after you find the shortest and longest.

Common mistakes

Not lining objects up at the same starting point before comparing — if one object starts farther ahead it will look longer even if it is shorter.
Mixing up shortest to longest and longest to shortest — always re-read the question to see which direction is asked for.
Forgetting the middle object — some kids only find the shortest and longest and skip placing the middle one correctly.
Thinking a fat or wide object is longer — length is only about how long something is from end to end, not how big around it is.
Guessing without comparing — always check all three objects against each other before writing your answer.

FAQs

Do the objects have to be the same kind of thing to compare their lengths?

No! You can compare any objects — a pencil and a shoe and a book can all be ordered by length even though they are very different things.

What if two objects are the same length?

That is totally fine. They share the same place in the order. You can say they are equal in length, and they both go in the same spot.

Does it matter which end I line the objects up from?

No, you can line them up from either end, but all three objects must start from the same side. If they do not start at the same point, the comparison will not be fair.

How do I find the middle object?

First find the shortest one and the longest one. The object that is left — the one that is not the shortest and not the longest — is the middle one.

What if I do not have a ruler? Can I still order objects by length?

Yes! You can lay the objects next to each other and line up one end to compare. Your eyes can tell you which one is shorter or longer without any numbers.

Why does my teacher say to start at the same end?

If objects do not all start at the same point, you are not measuring from the same place, so your comparison will be wrong. Think of a race — it is only fair if everyone starts at the same starting line.

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