Four Operations

The four operations — addition, subtraction, multiplication, and division — are the building blocks of arithmetic. On the CSSE maths paper, you will need to carry out calculations quickly and accurately, often as part of multi-step word problems. This lesson covers the key methods you need.

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Addition

Column Addition

Write numbers one below the other, lining up the ones, tens, hundreds, and so on. Always start from the right (the ones column).

Worked Example

Calculate 4,657 + 2,385

	Th	H	T	O
	4	6	5	7
+	2	3	8	5
=	7	0	4	2

• Ones: 7 + 5 = 12. Write 2, carry 1.
• Tens: 5 + 8 + 1 = 14. Write 4, carry 1.
• Hundreds: 6 + 3 + 1 = 10. Write 0, carry 1.
• Thousands: 4 + 2 + 1 = 7.

Answer: 7,042

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Subtraction

Column Subtraction (Decomposition)