Lesson Notes By Weeks and Term v4 - JHS 3
Number Operations
Download the Lessonotes Mobile Ghana app for faster lesson access on Android and iPhone.
Number Operations
Download the Lessonotes Mobile Ghana app for faster lesson access on Android and iPhone.
Subject: Mathematics
Class: JHS 3
Term: 1st Term
Week: 6
Grade code: B9.1.2.1.1
Strand code: 3
Sub-strand code: 2
Content standard code: B9.1.1.2
Indicator code: B9.1.2.1.1
Theme: GEOMETRY AND MEASUREMENT
Subtheme: Number Operations
This page supports the lesson note with a companion video and a short classroom-ready summary.
For class groups and homework, share this lesson page so learners also get the summary, objectives, and full lesson context.
This lesson focuses on a fundamental and powerful skill in mathematics: multiplying and dividing numbers by powers of 10 (like 10, 100, and 1000). This is not just a classroom trick; it is a skill we use every day in Ghana. When we calculate the cost of buying items in bulk at Makola market, convert Ghana Cedis to pesewas, or change measurements from metres to centimetres for sewing Kente, we are using powers of 10. Mastering this skill makes calculations faster, easier, and helps us understand the world of numbers better.
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 x 10 = 100 10³ = 10 x 10 x 10 = 1000 10⁴ = 10 x 10 x 10 x 10 = 10,000
Notice a pattern? The exponent (the small number at the top) tells you exactly how many zeros are after the 1. Part 1: Multiplying by Powers of 10
When we multiply a number by a power of 10, the number gets bigger. The shortcut is to move the decimal point to the RIGHT. To multiply by 10 (one zero), move the decimal point 1 place to the right. To multiply by 100 (two zeros), move the decimal point 2 places to the right. To multiply by 1000 (three zeros), move the decimal point 3 places to the right.