Double Century — Class 3 Mathematics (CBSE)

From the current NCERT Maths Mela Grade 3 book, Chapter 3. In cricket, two centuries make a "double century" — 200 runs. Here we count, read, and build numbers all the way to 200.

1. Why this chapter matters

After 100, numbers keep growing. Being able to read, write, and compare numbers up to 200 — and to estimate how many things there are — is useful every day, from counting laddoos to reading page numbers. This chapter makes big numbers friendly using bundles of tens and hundreds.

2. Core ideas

Idea 1 — Numbers grow past 100 to 200

One century is 100; two centuries make a double century, 200. The numbers 101, 102, 103 … go all the way up to 200.

Method 2 — Build numbers from hundreds, tens, and ones

145 = 1 hundred + 4 tens + 5 ones. Bundling helps us see how big a number is.

Skill 3 — Estimate, then count

First make a sensible guess (estimate), then count carefully to check.

3. Worked examples

Example 1: What is 1 hundred and 1 hundred together?

100 + 100 = 200 (a double century).

Example 2: Write 145 in hundreds, tens, and ones.

145 = 1 hundred, 4 tens, 5 ones (100 + 40 + 5).

Example 3: Which is greater, 132 or 123?

Both have 1 hundred. Compare the tens: 3 tens vs 2 tens. So 132 is greater than 123.

4. Activity corner

Take a big handful of beans or buttons. First estimate how many. Then make bundles of ten, count the bundles and the leftovers, and write the number. Answer in three parts:

• What I estimated
• What I counted (bundles of ten + ones)
• What maths idea this shows (grouping in tens to count big numbers)

5. Common mistakes

• Mistake: Writing 100-and-45 as "10045". Fix: One hundred forty-five is 145, not 10045.
• Mistake: Comparing only the last digit. Fix: Compare hundreds first, then tens, then ones.
• Mistake: Counting one by one and losing track. Fix: Make bundles of ten to count large groups quickly.

6. How to write better answers

1. Write the number in figures and, if asked, in words.
2. Break it into hundreds, tens, and ones.
3. To compare, line up hundreds, tens, and ones.
4. Write the final answer clearly.

7. Practice set

1. What number is 1 hundred more than 100?
2. Write 167 in hundreds, tens, and ones.
3. Which is greater: 158 or 185?
4. Write the number name for 130.
5. Count by tens from 150 to 200.
6. Estimate, then explain how bundles of ten help you count 174 beads.

8. Answer key

1. 100 + 100 = 200.
2. 167 = 1 hundred, 6 tens, 7 ones (100 + 60 + 7).
3. Both have 1 hundred; compare tens: 8 tens > 5 tens, so 185 is greater.
4. 130 is one hundred thirty.
5. 150, 160, 170, 180, 190, 200.
6. Estimate first (about 170–180). Then make 17 bundles of ten and 4 ones = 174; bundles make counting fast and accurate.

9. Quick revision

• One century is 100; a double century is 200.
• Numbers go 101, 102 … up to 200.
• Build numbers from hundreds, tens, and ones (145 = 1 hundred, 4 tens, 5 ones).
• Compare hundreds first, then tens, then ones.
• Estimate first, then count using bundles of ten.