Lesson Notes By Weeks and Term v4 - JHS 1

Lesson Video

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Performance objectives

• Explain what powers of 10 are.
• Multiply whole numbers by powers of 10.
• Divide whole numbers by powers of 10.
• Apply this skill to solve real-world problems.

Lesson summary

This lesson focuses on a very powerful shortcut in mathematics: multiplying and dividing numbers by powers of 10 (like 10, 100, 1000). This skill is not just for exams; it's a practical tool we use every day, often without realising it. When we talk about money (changing Cedis to pesewas), measure distances (metres to kilometres), or understand large numbers in the news about Ghana's population or economy, we are using powers of 10. Mastering this concept will make mental calculations faster and help build a strong foundation for more advanced topics like scientific notation.

Lesson notes

A. What are Powers of 10?

Powers of 10 are numbers you get when you multiply 10 by itself a certain number of times. They are the foundation of our number system (the decimal system). 10¹ = 10 10² = 10 × 10 = 100 10³ = 10 × 10 × 10 = 1000 10⁴ = 10 × 10 × 10 × 10 = 10,000

A simple way to remember this is: The exponent (the small number at the top) tells you how many zeros are after the 1. B. The Secret of the Decimal Point

Every number has a decimal point. Sometimes you see it, and sometimes it's "hiding". In a number like 45.72, you can see the decimal point. In a whole number like 68, the decimal point is hiding at the end: 68.0.