GRADE 3 MATHEMATICS – THEORY Notes Numbers • Addition • Subtraction • Multiplication • Shapes • Time • Roman Numerals by home academy

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GRADE 3 MATHEMATICS – THEORY Notes

Numbers • Addition • Subtraction • Multiplication • Shapes • Time • Roman Numerals

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Chapter 1 – Numbers

What are Numbers?

Numbers help us count, measure, compare, and solve problems.

Examples:

5 books

20 apples
300 students

Place Value

Every digit has a value depending on its position.

Example: 684

Hundreds	Tens	Ones
6	8	4

Value:

6 Hundreds = 600

8 Tens = 80
4 Ones = 4

Total = 684

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Number Names

We can write numbers in words.

Examples:

245 → Two hundred and forty-five

593 → Five hundred and ninety-three

870 → Eight hundred and seventy

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Numerals

Numbers written in digits are called numerals.

Examples:

Three hundred and twenty → 320

Nine hundred and four → 904

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Counting Patterns

Numbers may increase or decrease.

Example:
120, 130, 140, 150, 160

Rule: Add 10 each time.

Example:
495, 496, 497, 498, 499

Rule: Add 1 each time.

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Comparing Numbers

Use signs:

> Greater than

< Less than

= Equal to

Examples:

745 > 654

320 = 320

568 < 586

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Chapter 2 – Addition

What is Addition?

Addition means putting numbers together.

Symbol: +

Example:

245 + 123

245
+123
=368

Answer = Sum

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Steps for Addition

1. Add Ones

2. Add Tens

3. Add Hundreds

Example:

468 + 315

8 + 5 = 13
6 + 1 + carry = 8
4 + 3 = 7

Answer = 783

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Word Problems

Example:

Morning = 125 apples

Afternoon = 143 apples

125 + 143 = 268 apples

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Chapter 3 – Subtraction

What is Subtraction?

Subtraction means taking away.

Symbol: −

Example:

563 − 241 = 322

Answer = Difference

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Steps

Subtract:

• Ones

• Tens

• Hundreds

Example:

824 − 412 = 412

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Borrowing

Example:

700 − 325

Borrow when top digit is smaller.

Answer = 375

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Chapter 4 – Multiplication

What is Multiplication?

Multiplication means repeated addition.

Example:

3 × 4

4 + 4 + 4 = 12

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Multiplication Facts

2 × 5 = 10

4 × 6 = 24

5 × 8 = 40

7 × 7 = 49

8 × 8 = 64

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Easy Trick

Any number × 10

Add one zero.

Example:

6 × 10 = 60

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Chapter 5 – Shapes

Shapes are all around us.

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Triangle

3 sides

3 corners

Example:
Pizza slice

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Square

4 equal sides

4 corners

Example:
Window

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Rectangle

4 sides

Opposite sides equal

Example:
Book

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Circle

No sides

No corners

Example:
Clock

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Pentagon

5 sides

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Hexagon

6 sides

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Heptagon

7 sides

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Octagon

8 sides

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Chapter 6 – Time

Reading the Clock

Short hand = Hour hand

Long hand = Minute hand

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O’clock

3:00

Hour hand → 3

Minute hand → 12

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Half Past

6:30

Hour hand → Between 6 and 7

Minute hand → 6

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Quarter Past

9:15

Hour hand → Slightly after 9

Minute hand → 3

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Important Facts

1 hour = 60 minutes

1 day = 24 hours

1 week = 7 days

1 year = 12 months

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Chapter 7 – Roman Numerals

Roman numerals use letters.

Number	Roman Numeral
1	I
2	II
3	III
4	IV
5	V
6	VI
7	VII
8	VIII
9	IX
10	X
11	XI

Examples:

IV = 4

IX = 9

XI = 11

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Quick Revision

✓ Numbers and Number Names

✓ Addition

✓ Subtraction

✓ Multiplication

✓ Shapes

✓ Time

✓ Roman Numerals

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Practice at Home

1. Write number names from 100–999.

2. Learn multiplication tables 2–10.

3. Draw 5 different shapes.

4. Read clock time daily.

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