Maths Warm-Up: Broken Calculator ⭐️ The Sydney Teacher

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Maths Warm-Up: Broken Calculator

What happens when one calculator button stops working?

You end up with one of the most engaging maths warm-ups you'll ever run! Broken Calculator is a fun, no-prep challenge that gets students exploring different strategies.

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Broken Calculator

This is one of those maths warm-ups that looks simple at first, but don't let that fool you because it gets students thinking flexibly, sharing strategies, and proving there's rarely just one way to tackle a maths problem.

How It Works

Present this Broken Calculator challenge to your class:

Sally has a calculator with a broken 4 key. How could she use her calculator to find the answer to 34 × 42 without using the 4?

Challenge students to brainstorm as many different solutions as they can. Encourage them to explain their thinking and look for creative ways to rewrite the numbers.

Some Possible Answers:

(30 + 2 + 2) × (21 × 2)
(17 × 2) × (21 × 2)
(33 + 1) × (32 + 10)

There's no single "right" way to solve it, so encourage students to share and explain the different strategies they used.

Why It's So Good

• Builds number sense, flexible thinking, and problem-solving skills.

• Encourages students to explore multiple strategies instead of looking for one correct answer.

• Sparks rich mathematical discussions as students explain their reasoning.

• Gives you a quick insight into students' understanding.

• Takes just a few minutes and requires almost no preparation.

Next time you need a quick maths warm-up, give Broken Calculator a go. It's easy to run, gets the whole class involved, and always leads to interesting conversations!

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