One-to-One Correspondence

Learn how to use one-to-one correspondence to teach early math skills.

One-to-One Correspondence

One-to-One Correspondence

One-to-one correspondence is an important beginner math skill that children learn in their formative years. Using activities that incorporate one-to-one correspondence can teach crucial math concepts that build the foundation for children to develop more complex math skills. Below, we’ll define what one-to-one correspondence means, discuss its importance, and share strategies for teaching it to young children.

A child sitting at a table with a bin of multi-colored pom poms on the right and a green animal with a brown hump that has hallow cardboard circles on it on the left. There is a pom pom in almost every hole.Source

What is one-to-one correspondence?

One-to-one correspondence is an early math skill that involves a child's ability to count in ascending order while touching or transferring each object in a set, one by one, and only once. It is a skill that families and teachers can teach toddlers and preschoolers to help them understand the rules of counting.


In one-to-one correspondence activities, children count several objects. As they count, they touch or move each object, assigning one number to each object that they move. Children who have mastered one-to-one correspondence will not skip numbers or touch an object more than once. 

Why is one-to-one correspondence important in developing math skills in young children? 

Adults use one-to-one correspondence skills daily and probably don’t even realize it. When using a recipe, you need to know how much of each ingredient you need, and that is based on how many servings you want your dish to yield. When you’re paying for those ingredients at the grocery store, you need to know how much money to pay the cashier. When the time comes to feed your family or guests, you’ll use one-to-one correspondence to determine one serving size for each person. 

As a teacher, you often use one-to-one correspondence to calculate how many crayon boxes, glue sticks, and other materials you need for your children.  As you can see, one-to-one correspondence is used a lot in our day-to-day activities. 

One of the benefits of learning one-to-one correspondence at an early age is that it sets the stage for learning basic math concepts such as addition and subtraction.  Eventually, it helps children with more complex math skills such as multiplication and algebra. Without the foundation of developed one-to-one math skills, children will most likely struggle with basic math concepts.

A teacher and child lying on a purple mat with little yellow, blue, red, and green plastic bears lined in rows according to color in front of them.Source

How to teach one-to-one correspondence 

Children start learning to count between the ages of one and two years old. Some toddlers can count to 10 by the time they turn two. When children first start counting, they recite numbers randomly, or they may skip numbers or say them out of order. At first, toddlers are most likely reciting numbers from memorization without truly understanding what the numbers mean or represent. 

When children begin to recite numbers in order from memory, this is called rote counting. Rote counting is the first step to learning how to count. Rote counting is an essential step in knowing how to associate each number with the correct number symbol and learning the correct sequential order, such as “one, two, three, four, five….” 

Children must master the order of counting before they can begin to learn one-to-one correspondence. Once children master rote counting, there are several strategies and activities you can use to teach one-to-one correspondence.

Here are some tips and techniques you can use to help the children in your class learn one-to-one correspondence:  

One-to-one teaching techniques

  • Use everyday classroom opportunities to practice counting one-to-one.  For example, you can ask the children to help pass out supplies. When they do, they can count the right amount of supplies that corresponds with the number of students. This will help children understand that the quantity of supplies counted is equal to the quantity of students. You can even have children count their snacks, such as Goldfish crackers or Cheerios, one-to-one.
  • Count slowly so that children can truly catch on to the rules of counting. 
  • Try activities that include the numerals so that children can start to associate the correct quantity with its corresponding number. You can have them write or trace the numerals, or you can provide the numerals on worksheets or within the activities.
  • Start off using pre-filled frame counting mats. Then, show the children how to count one-to-one in each frame and have the children do it after you. You can start off using only five frames on a 10-frame mat, or you can fill the entire 10 frames.

Activities to promote one-to-one correspondence

Counting jewels one-to-one activity


A bin filled with multi-colored flat marbles in the bottom left corner.  In the middle of the table are three cards: the first numbered 1, the second numbered 2, and the third numbered 3 at the bottom of each card. There is a rainbow at the top of each card. Under card one is one marble, under card two is two marbles, and under card three, a child is placing three flat marbles.Source

What you need: 

  • Paper or flashcards
  • Writing utensils 
  • Jewels 

How to play:

  • Draw a rainbow or any other shape of choice on a piece of paper. 
  • On the paper, write a number under each shape.
  • Pour the jewels into a bowl or onto a table. 
  • Have the children count the number of jewels associated with the number under each shape and place them beneath the paper. 


Counting goldfish one-to-one activity


A worksheet titled "1 Fish 2 Fish"  that has two rows of goldfish bowls. The first row has three bowls numbered 1, 2, 3 consecutively. And the second row has three bowls numbered 4, 5, 6, consecutively. Each bowl has the corresponding amount of goldfish crackers placed on top of it. Source

What you need: 

  • Goldfish counting worksheet
  • Writing utensils 
  • Goldfish crackers

How to play:

  • Using a dice, roll it and ask your children to count the dots.
  • Have the children count the same number of goldfish as dots rolled on the dice and place the goldfish inside the goldfish bowl that has the corresponding number. 

With this game, you can also use Cheerios or similar types of snacks. As children learn to count beyond 6, add another dice and more numbers. 

Popsicle sticks one-to-one activity


Four popsicle sticks: the first painted yellow, with the number 1 at the bottom; the second painted blue, with the number 2 at the bottom; the third painted red, with the number 3 at the bottom; and the fourth painted green, with the number 4 at the bottom. There are seven clothespins to the right of the popsicle sticks.


What you need: 

  • Popsicle sticks
  • Clothespins 
  • Sharpie 

How to play: 

  • Write a number (1-5) at the bottom of each popsicle stick. 
  • Draw corresponding lines or circles on each popsicle stick. For example, draw one line on the popsicle stick labeled ‘1’.
  • Optional: If your popsicle sticks are colored, color the clothespins to match the colors of the popsicle sticks. Otherwise they can be plain.  
  • Have children match the correct number of clothespins to each popsicle stick.

This activity is also a great way to sharpen fine motor skills, and concentration skills because the children must pinch the clothes pins and attach them to the popsicle sticks.

Ice cube tray one-to-one activity


A child in a yellow shirt standing in front of white ice tray and a blue bin filled with pom poms on a purple tray. The child is placing one pom pom in each section of the ice tray.Source

What you need: 

  • Ice cube tray or muffin container 
  • Dice
  • Objects of choice to fill the tray 
  • Writing utensil 

How to play:

  • Have the child roll the dice and count the number of dots on the dice.  
  • Have the child place the correct number of objects in each cube. 


  • Write a number at the bottom of each cube tray or muffin-tin space. 
  • Have the child count the objects and fill the tray or space with the quantity of objects corresponding with the number.

When you use your imagination and get creative, there are so many exciting ways to teach children how to count one-to-one.

One-to-one correspondence FAQs

How do you know when children have mastered one-to-one correspondence? 

A child who has mastered one-to-one will have mastered these four principals:

  • Each object is assigned only one numeral. 
  • The number names are counted in a fixed, ascending order. 
  • No matter what object the child starts counting with or ends counting with, the end quantity is the same. 
  • The final number counted is the total number, or the cardinal number.

What should you do if a child is struggling with one-to-one? 

Pay close attention to whether the child has mastered the four areas listed above. If you find that the child is struggling in any of those areas, let that become the main area that you focus on helping the child to grow in. 

There are questions you should ask as you observe children counting one-to-one: 

  • Are they touching, tapping, or pointing to each object once?
  • Do they say all the numbers in order, or are they missing any? 
  • Do they remember how many they counted or what the final number is?

Is one-to-one a prerequisite for kindergarten?

Children should understand one-to-one correspondence; however, they will gain an even deeper understanding during kindergarten. 

Add one-to-one correspondence to your curriculum 

There are so many ways and activities you can use to teach children one-to-one correspondence. Remember that children must first learn how to count in rote order before they can learn one-to-one, and since children develop at their own pace, they may master rote counting and one-to-one at different times. When it comes to one-to-one, practice makes perfect. Be sure to use every opportunity possible to teach the children in your classroom using one-to-one correspondence techniques. 

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