Tens and Ones
Numbers up to 99: Tens and Ones
Tens and Ones
Tens and Ones
NCERT anchor: NCERT Joyful Mathematics Class 1 — Chapter 11: How Many Tens, How Many Ones? (bundles of ten)
What you'll learn
- Group objects into bundles of ten and count leftover ones.
- Read a two-digit number as a certain number of tens and ones.
- Build numbers up to 99 using tens and ones.
Key concepts
1. A bundle of ten
Ten single sticks tied together make 1 bundle of ten. A bundle of ten is worth exactly 10 loose sticks.
2. Reading tens and ones
The number 34 means 3 tens and 4 ones (3 bundles of ten, plus 4 loose ones). The first digit tells the tens, the second digit tells the ones.
3. Building a number from tens and ones
5 tens and 2 ones = 50 + 2 = 52. Always write the tens digit first, then the ones digit.
4. Zero ones
A number like 30 has 3 tens and 0 ones — no loose sticks left over.
Worked example
Counting pencils in bundles
Step 1 — Meena has 4 bundles of 10 pencils each, and 3 loose pencils.
Step 2 — Tens: count the bundles → 4 tens.
Step 3 — Ones: count the loose pencils → 3 ones.
Step 4 — Put them together: 4 tens and 3 ones = 40 + 3.
Answer: Meena has 43 pencils in all.
Common mistakes
| Mistake | Why | Fix |
|---|---|---|
| Swapping tens and ones | Writing 43 as 34 | Always say "tens" first, then "ones," and write digits in that order |
| Forgetting a loose one | Miscounting leftover objects | Circle each bundle of ten first, then count what remains outside |
| Thinking 0 ones means no number | Confusing "0 ones" with "nothing" | 30 still has 3 tens even though it has 0 ones |
Quick check
- How many tens and ones are in 27?
- Which number has 6 tens and 1 one?
- Arjun has 5 bundles of 10 marbles and 6 loose marbles. How many marbles in all?
- Stretch: A number has 7 tens and 0 ones. What is the number?
Revision tip: Use ice-cream sticks or matchsticks at home — bundle 10 together with a rubber band and practise reading tens and ones.
Open the Practice tab for graded questions on Tens and Ones.
Key Takeaways (TL;DR)
- What you'll learn
- Key concepts
- Worked example
- Common mistakes
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