Class 4 Maths Practice Book

Key Concepts

Adding and subtracting numbers up to 10,000 helps you find totals and differences quickly. We use these skills when counting money, books, points, or toys.

• Line up ones, tens, hundreds, and thousands in straight columns.
• Add from the ones column first.
• If a column total is 10 or more, regroup 10 ones as 1 ten.
• Subtract from the ones column first.
• If the top digit is too small, regroup 1 ten as 10 ones.
• Check addition by estimating or using subtraction.

Before you continue: Can you explain why we regroup when a column has 10 or more?

Key Terms

Place value - The value of a digit because of its place, such as ones, tens, hundreds, or thousands.

Regroup - To exchange 10 of one place for 1 of the next place.

Carry - To move an extra ten, hundred, or thousand to the next column when adding.

Borrow - To take 1 from the next column and change it into 10 in the column we need.

Sum - The answer to an addition problem.

Difference - The answer to a subtraction problem.

Active Recall

Place value

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Regroup

__________

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Carry

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Borrow

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Sum

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Difference

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Worked Examples

Example 1: Addition

Add 2,468 + 1,357.

1. Ones: 8 + 7 = 15. Write 5 and carry 1 ten.

2. Tens: 6 + 5 + 1 = 12. Write 2 and carry 1 hundred.

3. Hundreds: 4 + 3 + 1 = 8.

4. Thousands: 2 + 1 = 3.

So, 2,468 + 1,357 = 3,825.

Now you try: 3,276 + 2,458 = __

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Example 2: Subtraction

Subtract 4,203 - 1,786.

1. Ones: 3 is too small, so regroup 1 ten. There are 13 ones.

2. 13 - 6 = 7.

3. Tens: 9 is too small, so regroup 1 hundred. There are 19 tens.

4. 19 - 8 = 11. Write 1 and regroup 1 thousand.

5. 3 hundreds - 7 hundreds is not possible, so regroup carefully: 4 thousands becomes 3 thousands and 13 hundreds. Then 13 - 7 = 6.

6. 3 - 1 = 2.

So, 4,203 - 1,786 = 2,417.

Now you try: 5,012 - 2,684 = __

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Example 3: Word Problem

A shop has 3,475 red pencils and 2,268 blue pencils. How many pencils are there altogether?

Add: 3,475 + 2,268 = 5,743 pencils.

Practice Questions

1. (Easy) Add 1,245 + 2,312.

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2. (Easy) Subtract 3,876 - 1,245.

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3. (Medium) Add 4,687 + 3,956.

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4. (Medium) Subtract 8,004 - 2,679.

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5. (Medium) A library has 2,735 storybooks and 1,846 science books. How many books are there?

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6. (Hard) A stadium had 9,000 seats. If 4,786 seats were filled, how many seats were empty?

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Answer Key

1. 3,557

2. 2,631

3. 8,643

4. 5,325

5. 4,581 books

6. 4,214 seats

Exam Tips & Common Mistakes

• Do not mix up the columns. Write ones under ones and tens under tens.
• Remember the carried digit. Circle it lightly so you do not forget it.
• When subtracting, check whether the top digit is big enough before subtracting.
• Add neatly. A messy column can change the answer.
• Read word problems carefully. Words such as “altogether” usually mean addition. Words such as “left” or “difference” usually mean subtraction.
• Show your working. It helps you find small mistakes.
• Check your answer with an estimate....