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Year 4 Mathematics Number & Algebra AC9M4N04

Mental Maths Strategies

Mental maths means calculating in your head without writing. Good strategies make mental calculations faster and more accurate.

What You Need to Know

Key Concept Diagram

Doubles and near-doubles: knowing 7+7=14 helps with 7+8=15

Compatible numbers add up to a round number, e.g. 6+4, 25+75

Bridging through 10: to add 8+5, think 8+2+3=13

Front-end estimation rounds numbers to the leading digit for a quick estimate

Key Vocabulary

Mental computation

Calculating the answer in your head without writing

Compatible numbers

Numbers that are easy to work with mentally, often adding to 10 or 100

Bridging

A strategy where you add up to a round number, then add the rest

Near doubles

Facts close to a double, like 6+7 = double 6 + 1

Knowledge Check

Select the correct answer for each question. Click "Check Answer" to see if you are right.

Question 1

Using bridging through 10: 7 + 6 = ?

Question 2

What is a good mental maths strategy for 25 + 37?

Question 3

99 + 47 = ?

Key Concepts Summary