Problem Solving - Choosing the appropriate operation for word problems

Grade 3IGCSE

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

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Understanding the RUCSAC method: Read, Understand, Choose, Solve, Answer, Check.

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Addition Keywords: Total, sum, altogether, both, in all, plus, increase.

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Subtraction Keywords: Difference, how many more/less, left, remain, decrease, take away.

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Multiplication Keywords: Product, times, each, groups of, per, double/triple.

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Division Keywords: Share equally, split, divide, groups of, each gets, half.

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Visualizing the problem: Drawing bar models or arrays to help decide if the total is getting larger or smaller.

📐Formulae

\text{Part} + \text{Part} = \text{Whole}

\text{Whole} - \text{Part} = \text{Remaining Part}

\text{Number of Groups} \times \text{Size of Group} = \text{Total}

\text{Total} \div \text{Number of Groups} = \text{Size of each Group}

💡Examples

Problem 1:

A bakery has 45 chocolate muffins and 38 blueberry muffins. How many muffins are there altogether?

Solution:

45 + 38 = 83

Explanation:

The word 'altogether' indicates that we need to combine two groups to find a total, so we use addition.

Problem 2:

50. He spent

Solution:

50 -

Explanation:

The phrase 'have left' indicates that an amount has been taken away from the whole, so we use subtraction.

Problem 3:

There are 6 tables in a classroom. Each table has 4 chairs. How many chairs are there in total?

Solution:

6 \times 4 = 24

Explanation:

We have equal groups (6 tables) with the same amount in each (4 chairs). To find the total of equal groups, we use multiplication.

Problem 4:

A teacher has 20 pencils and wants to share them equally among 5 students. How many pencils does each student get?

Solution:

20 \div 5 = 4

Explanation:

The phrase 'share equally' tells us to split a total into equal groups, which requires division.