What is Counting in Elevens?

S0-SA1-1440

Grade Level:

Pre-School – Class 2

All domains without exception

Definition

What is it?

Counting in Elevens means adding 11 repeatedly to a starting number to get the next number in a sequence. It's a way of skip counting where the 'skip' or jump size is always 11.

Simple Example

Quick Example

Imagine you are collecting 'laddus' for a festival. If you start with 0 laddus and add 11 laddus each time, you would have 0, then 11, then 22, then 33, and so on. This is counting in elevens.

Worked Example

Step-by-Step

Let's count in elevens starting from 5.

1. Start with the given number: 5
---2. Add 11 to the starting number: 5 + 11 = 16
---3. Add 11 to the new number: 16 + 11 = 27
---4. Add 11 to the new number: 27 + 11 = 38
---5. Add 11 to the new number: 38 + 11 = 49
---So, counting in elevens from 5 gives the sequence: 5, 16, 27, 38, 49, and so on.

Why It Matters

Counting in elevens helps build strong number sense and is a foundation for multiplication and division. It's useful in careers like finance for calculating interest over specific periods, or in logistics for estimating quantities in batches, and even for programmers dealing with data structures.

Common Mistakes

MISTAKE: Adding 1 instead of 11. Forgetting the 'skip' amount. | CORRECTION: Always remember the specific number you are counting by. Here, it's 11, so always add 11.

MISTAKE: Losing track of the previous sum and restarting from the original number. | CORRECTION: Each time you add 11, use the *new total* as your starting point for the next addition.

MISTAKE: Confusing counting in elevens with counting by other numbers like tens or twenties. | CORRECTION: Pay close attention to the number specified for skip counting. If it says 'elevens,' always use 11.

Practice Questions

Try It Yourself

QUESTION: Count in elevens, starting from 0, for the first five numbers. | ANSWER: 0, 11, 22, 33, 44

QUESTION: If a bus ticket costs Rs 11, and you buy 4 tickets, how much do you pay by counting in elevens? | ANSWER: Rs 44 (11 + 11 + 11 + 11 = 44)

QUESTION: A gardener plants flowers in rows. Each row has 11 flowers. If they have already planted 3 rows, how many flowers have they planted in total? How many more flowers do they need to plant to reach 5 rows? | ANSWER: 33 flowers planted (11+11+11 = 33). Need 22 more flowers (11+11 = 22) to reach 5 rows (55 total flowers).

MCQ

Quick Quiz

What is the next number in the sequence when counting in elevens: 2, 13, 24, __?

The Correct Answer Is:

To find the next number, add 11 to the last number in the sequence. 24 + 11 = 35. Options A, B, and D are incorrect as they do not follow the 'add 11' rule.

Real World Connection

In the Real World

Imagine you are a shopkeeper in a 'kirana' store, and you sell 'agarbattis' (incense sticks) in bundles of 11. To quickly calculate how many sticks are in 7 bundles, you would count in elevens (11, 22, 33, 44, 55, 66, 77). This helps you keep track of your stock or calculate total items for a customer.

Key Vocabulary

Key Terms

COUNTING: The process of determining the total number of items in a set | SKIP COUNTING: Counting by a number other than one, like by twos, fives, or elevens | SEQUENCE: An ordered list of numbers or objects | ADDITION: The process of combining two or more numbers to find their sum

What's Next

What to Learn Next

Now that you understand counting in elevens, you can explore counting in twelves or other numbers. This will strengthen your understanding of multiplication tables and help you solve more complex arithmetic problems faster.