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Kindergarten · K.MD.A.1 · K.MD.A.2

Longer and shorter in kindergarten

Longer and shorter are some of the first measurement words in school math. In kindergarten, your child learns that objects have features you can measure, such as length and weight. Your child then puts two objects side by side and says which one is longer, taller or heavier.

What the standards say

The official Common Core wording, quoted exactly. The plain version follows.

K.MD.A.1 Describe measurable attributes of objects, such as length or weight. Describe several measurable attributes of a single object.

K.MD.A.2 Directly compare two objects with a measurable attribute in common, to see which object has "more of"/"less of" the attribute, and describe the difference.

What it means, in plain words

Things you can measure K.MD.A.1

A feature you can measure is one that can be more or less: how long something is, how heavy it is or how much it holds. Kindergarten measurement starts with words, not rulers. Long, short, tall, heavy, light, full and empty are all measurement words.

Length is how long something is from one end to the other. Height is length going up, so a tree is tall rather than long. Weight is how heavy something is, and your child feels it by holding the object.

One object has several of these features at once. A full backpack is long and heavy, and it holds a lot. A shoelace is long and light. Your child learns that "big" can mean many different things and starts to say which one is meant.

Your child should be able to:

  • Name features of an object that can be measured, such as its length or its weight
  • Describe one object in more than one way, like long and light
  • Use measurement words such as long, short, tall, heavy, light, full and empty

Example

A bucket is full of sand. What can your child say about it that could be measured?

  1. How tall it is: the bucket comes up to your child's knee.
  2. How heavy it is: it is hard to lift with one hand, so it is heavy.
  3. How much it holds: it is full of sand.
  4. So one bucket can be described by its height, its weight and how much it holds.

Comparing two objects K.MD.A.2

Comparing length means putting two objects side by side and saying which one is longer and which one is shorter. The key step is to line up one end of each object. If one object starts further along, it can look longer when it is not.

Heavier and lighter work the same way. Your child holds one object in each hand, or uses a simple balance, and says which one is heavier. On a balance, the heavier side goes down.

Longer and shorter in kindergarten always means comparing two real objects directly, with no numbers. Measuring with units, such as paper clips laid end to end, comes in 1st grade, and rulers come in 2nd grade. Your child should also learn to say a comparison both ways: "the wooden spoon is longer than the teaspoon" and "the teaspoon is shorter than the wooden spoon".

Your child should be able to:

  • Line up two objects at one end and say which one is longer
  • Say which of two objects is taller and which is shorter
  • Hold two objects and say which one is heavier and which one is lighter
  • Describe a comparison both ways, with "longer than" and "shorter than"

Example

Which is longer, a wooden spoon or a teaspoon?

  1. Lay both spoons on the table, side by side.
  2. Push their handle ends against the same edge, such as the side of a book, so they start at the same place.
  3. Look at the other end. The wooden spoon goes past the teaspoon.
  4. The wooden spoon is longer, and the teaspoon is shorter.

Example

Which is heavier, an apple or a grape?

  1. Hold the apple in one hand and the grape in the other.
  2. The hand with the apple feels pulled down more.
  3. The apple is heavier, and the grape is lighter.

Where children usually get stuck

  • Your child looks at two straws that do not start at the same place and picks the one that sticks out further.

    The child compares only the far ends and does not check where each object starts.

    What helps. Make "line them up" the first step every time. Push both objects against the edge of the table before anyone says which is longer.

  • Your child says a pillow is heavier than a can of soup because the pillow is bigger.

    Young children expect bigger things to be heavier. Size and weight feel like the same thing until a child holds objects that break that rule.

    What helps. Put the pillow in one of your child's hands and the can in the other. Ask which one pulls the arm down more.

  • Your child uses "big" for everything: a tall glass, a long train and a heavy box are all big.

    "Big" is the size word a young child knows best. The child has not yet learned that tall, long and heavy each name a different feature.

    What helps. When your child says "big", ask back: "Big how? Long, tall or heavy?" Then use that word in your answer.

Try four practice questions

Real kindergarten questions from our question bank, easiest first. Answer them right here, check each one, and see a worked solution for any question.

  1. 1Warm-up
    What is being measured in the picture below?
    Length comparison (2 objects, length, clear-gap)
    A
    Length
    B
    Weight
    C
    How much it holds
    Show the answer and how to solve it

    The answer is Length. The pencils are lined up next to each other to show how long each one is, and how long something is is called its length.

    1. 1Look at the picture. Two pencils are lined up next to each other.
    2. 2When we line things up next to each other, we can see how long each one is. That is its length.
    3. 3The picture is not lifting the pencils to feel how heavy they are (weight). It is not showing what fits inside the pencils (how much they hold). It is showing how long they are.
    4. 4The answer is Length.

    Common mistake. A common mistake is choosing 'Weight' just because pencils are solid objects. Look at WHAT the picture is showing: are the pencils on a scale, or are they lined up to compare how long they are?

    The idea underneath. When we line things up next to each other to see which one reaches farther, we are comparing their length.

  2. 2On level
    Look at the picture below. Which sentence is true?
    Length comparison (2 objects, green→orange, moderate)
    A
    The orange crayon is longer than the green crayon.
    B
    The green crayon is the same length as the orange crayon.
    C
    The green crayon is shorter than the orange crayon.
    D
    The green crayon is longer than the orange crayon.
    Show the answer and how to solve it

    The correct sentence is: "The green crayon is longer than the orange crayon." The green crayon reaches farther than the orange crayon, so it is longer.

    1. 1Look at the two crayons. See how far each one reaches.
    2. 2The green crayon reaches farther than the orange crayon. So the green crayon is longer.
    3. 3Find the sentence that says the green crayon is longer than the orange crayon.

    Common mistake. A common mistake is mixing up which crayon is longer or using the wrong word like "shorter" or "same." Always look at how far each crayon reaches and pick the word that matches.

    The idea underneath. When you compare two objects, look at how far each one reaches. The one that reaches farther is the longer one.

  3. 3On level
    Sam looked at the picture below.
    Length comparison (2 objects, capacity, clear-gap)
    Sam said it shows length. Is Sam right?
    A
    Yes, that's correct
    B
    No, it shows how much it holds
    C
    No, it shows weight
    Show the answer and how to solve it

    The correct answer is 'No, it shows how much it holds.' The picture shows glasses being filled with juice, which is about how much fits inside each glass.

    1. 1Look at the picture. The glasses are being filled with juice.
    2. 2When we fill a glass, we are showing how much juice fits inside. That is how much it holds.
    3. 3Sam said the picture shows length. But length is how long something is. The glasses are being filled, so the picture shows how much they hold — not how long they are. Sam is not right.

    Common mistake. A common mistake is to look at the tall shape of the glasses and think the picture shows length. But the picture is about what is being DONE in it. The glasses are being filled, so the picture shows how much they hold — not how long they are.

    The idea underneath. What you measure depends on what is happening in the picture. Filling shows how much it holds. Lining up or stretching out shows length. A balance scale shows weight.

  4. 4Stretch
    Lin looks at the two cups in the picture and wants to find which cup holds more water. Lin says, "The blue cup holds more water." Pick the answer about Lin's claim.
    Length comparison (2 objects, red→blue, moderate)
    A
    Yes. The blue cup holds more water than the red cup.
    B
    No. The red cup holds more water than the blue cup.
    C
    No. The blue and red cups hold the same.
    D
    No. The blue and red cups are different sizes.
    Show the answer and how to solve it

    Lin is wrong. The red cup holds more water than the blue cup.

    1. 1Look at the two cups in the picture. The red cup has water up high. The blue cup has water down low. The red cup is more full than the blue cup.
    2. 2Lin said, "The blue cup holds more water." Now check the picture. The red cup is the more-full one, not the blue cup.
    3. 3Lin is wrong. Pick "No. The red cup holds more water than the blue cup."

    Common mistake. A common mistake is just trusting what a classmate says. Always check the picture first — the red cup is more full.

    The idea underneath. Sometimes a classmate is right and sometimes wrong. Always check the picture before you agree or disagree.