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Maths 1 · Natural Numbers

Sainik School · Class 6 Entrance

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SECTION A · MATHEMATICS · TOPIC 1

Natural Numbers 🔢

Maths carries 150 of the 300 marks — half the paper. And almost every maths question starts with reading a number correctly. Get this chapter right and the rest becomes easier.

🏷️

Part 1 · Place Value

⚖️

Part 2 · Compare & Round

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Part 3 · Number Properties

1

Place Value & Number Systems 🏷️

Natural numbers are the counting numbers: 1, 2, 3, 4, … They never end, and 0 is not a natural number. Add 0 and they become whole numbers.

🇮🇳 Indian System

PeriodPlaces
OnesOnes, Tens, Hundreds
ThousandsTh, Ten Th
LakhsLakh, Ten Lakh
CroresCrore, Ten Crore

Commas after 3, then every 2 digits:

3,45,678

Three lakh forty-five thousand six hundred seventy-eight

🌍 International System

PeriodPlaces
OnesOnes, Tens, Hundreds
ThousandsTh, Ten Th, Hundred Th
MillionsMillion, Ten M, Hundred M
BillionsBillion …

Commas after every 3 digits:

345,678

Three hundred forty-five thousand six hundred seventy-eight

🔑

The two words examiners love to mix up:

Face value = the digit itself.   Place value = digit × its place.

In 47852: the face value of 7 is 7, but its place value is 7 × 1000 = 7000.

🔍 Break up 5,84,209 (Indian system)

Ten LakhLakhTen ThThHundredTenOne
584209
5,00,00080,0004,00020009

Expanded form: 5,00,000 + 80,000 + 4,000 + 200 + 0 + 9

📘 Solved for you, step by step

Try each one on rough paper first.

⌨️

Game 1 — Place Value Drill

2

Comparing, Ordering & Rounding ⚖️

⚖️ How to compare two numbers

  1. Count the digits. More digits = bigger number.
  2. If the digit count is equal, compare from the left.
  3. Stop at the first place where they differ.

58,214 vs 58,092 → same digits; 5=5, 8=8, then 2 > 0, so 58,214 is bigger.

🎯 Rounding off

Look at the digit just to the right of the place you are rounding to:

  • • If it is 0,1,2,3,4 → round down (keep the digit)
  • • If it is 5,6,7,8,9 → round up (add 1)

4752 to the nearest hundred: the tens digit is 5 → round up → 4800.

🔁 Successor, predecessor & making numbers

Successor

the number just after → n + 1
successor of 4999 = 5000

Predecessor

the number just before → n − 1
predecessor of 7000 = 6999

Greatest / smallest

Greatest: big digits first.
Smallest: small digits first, but never start with 0.

Classic trap: using the digits 5, 0, 3, 7 — the smallest 4-digit number is 3057, not 0357. A number cannot begin with 0. The greatest is 7530.

🎯

Game 2 — Compare & Round

3

Number Properties 🧮

These four properties turn slow sums into fast ones. Examiners test them directly, too.

⚠️

Careful: subtraction and division are not commutative. 8 − 3 ≠ 3 − 8, and 8 ÷ 2 ≠ 2 ÷ 8. Only addition and multiplication can be reordered freely.

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Game 3 — Match the Property

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Topic Mock Test

12 AISSEE-style questions. Remember: in the real paper each maths question is worth 3 marks, and there is no negative marking — so never leave one blank. 🍀

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