MathematicsCounting Objects One at a Time
Lumi sits at a cozy wooden table covered with a cheerful pile of colorful apples, pointing to each apple one by one with a big smile, counting carefully while touching each fruit.
- Count a group of up to 10 objects by touching each one exactly once.
- Say the number words in the correct order from one to ten.
- Identify the last number said as the total number of objects in the group.
- Demonstrate one-to-one tagging by counting a set of objects without skipping or repeating any.
Key terms
- counting
- Saying number words in order while tagging each object once.
- one-to-one correspondence
- Matching exactly one number word to each single object.
- cardinality
- The idea that the last number said tells the total.
- number word
- A word like one, two, or three that names an amount.
One Touch, One Number
Careful counting means each object gets exactly one number word and no object is skipped or counted twice. A helpful way to do this is to touch or move each object as you say its number. If you point but skip an object, your total will be too small; if you touch the same object twice, your total will be too big.
The Last Number Counts
When you finish counting, the very last number word you say is the answer for how many objects there are in all. This special idea is called cardinality. The last number is not just the name of one object — it stands for the whole group you just counted, so it is the total amount.
Worked examples
Count three apples on the table.
- Touch the first apple and say one.
- Touch the second apple and say two.
- Touch the last apple and say three.
Answer: 3 apples
Count five blocks in a row.
- Touch each block once, in order.
- Say one, two, three, four, five as you touch.
- The last number you said was five.
Answer: 5 blocks
Activity
Touch each object one time as you count out loud. How many are there in all?
Practice
Touch and count six crayons, saying each number out loud once.
A friend counts and says one, two, two; explain what went wrong.
Common mistakes to avoid
- The last number names one objectThe last number you say tells how many objects are in the whole group, not just the final object.
- It is fine to skip aroundSkipping or recounting an object gives the wrong total, so touch each object exactly one time in order.
Check your understanding
Lumi counts 5 blocks. She touches each block one time. What does the number 5 tell us?
A child counts these 4 fish: he says 'one, two, three, three' and points to a different fish each time. What went wrong?
There are 6 apples on the table. You count them all correctly. What is the last number you say?
Recap
To count, say number words in order and touch each object exactly once, never skipping or repeating any. The last number you say tells you how many objects are in the whole group, which is called the total.
Reflect
Where in your day do you need to count carefully so you do not miss anything?