## Math 9, Lesson 15, Spring 2016, 6/12/2016

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We have our final exam today. We will go over the exam next Sunday, which is the last day of the school for Spring 2016.

## Math 9, Lesson 14, Spring 2016, 6/5/2016

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We review statistics and probability.

Howework: #11 – #20 with the following pages

## Math 9, Lesson 13, Spring 2016, 5/22/2016

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We study tables, charts, and graph, in particular we study distance-time graphs and speed-time graphs.

In our earlier classes (Math 7), students should have learned the basics of reading, interpreting and graphing of tables, charts, and graphs, as well as working with distance-time graphs.

So we focus on study speed-time graphs which can contain more information about the motion of an object than that of a distance-time graph.

With a speed-time graph, we can calculate acceleration, as well as calculating distance traveled, which is the area under the speed time graph.

Homework:

From the workbook, Page 50: #5- #13, #15 – #18.

## Math 9, Lesson 12, Spring 2016, 5/15/2016

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We review coordinate geometry  and vectors in two dimensional space.

Homework: download Page 1, Page 2, Page 3

#1 – #6, #12 – #17

## Math 9, Lesson 11, Spring 2016, 5/8/2016

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We finish going over the remaining math contest questions.

We study money exchange and talk about the difference between selling and buying price in real world for money exchange.

We study taxation focusing on individual income tax and property tax. Note, the book talks about Singapore personal income tax and property tax, which is different than the US system. But the concept is the same and hopefully that the students will know how to apply what they learn to real world situations.

Homework:

Workbook: Page 43: #9 – #12, #19 – #22, #26, #27

## Math 9, Lesson 10, Spring 2016, 5/1/2016

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We go over the math contest questions today. Students will get their papers back. Please help them go over the questions.

## Math 9, Lesson 9, Spring 2016, 4/10/2016

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We have school wide math contest today. All students taking NCLS math classes participate.

We will go over the contest next lesson, which will be 5/1/2016. There is no school for the next two Sundays.

## Math 9, Lesson 8, Spring 2016, 4/3/2016

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We discuss installment calculation and how to read utility bills.

And next week will be the school wide math contest. All students taking Math classes will participate.

Homework:

Workbook Page 41, #5 – #8, #17, #18, #23, #24

## Math 9, Lesson 7, Spring 2016, 3/27/2016

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We move on to the chapter about mathematics in practical situations, and today we study profit, loss, simple interest, and compound interest. These topics are not new for most students.

Profit is achieved when the selling price is bigger than the cost price. The difference is the profit. Profit over the cost defines the profit percentage.

When the selling price is lower than the cost, you have a loss, which is defined as the difference between the cost and the selling price. The loss over the cost defines the cost percentage.

Banking usually deals with interest. The original amount you deposit into a bank account is called the principal. The interest is calculated based on an interest rate, which usually is given as an annual percentage.

In simple interest calculation, the interest calculation is based solely on the principal. So interest \$I earned on the principal \$P at the interest rate of i% annually for a period of n years is given by:

I = P x i% x n

In compound interest calculation, interest is calculated on prior interest accumulated over a period of time. Suppose an initial principal \$P is invested at i% per period with compound interest for n periods, let An be the amount after n periods, then:

An = P(1 + i%)^n

Homework:

Workbook Page 41, #1 – #4, #13 – #16.

## Math 9, Lesson 6, Spring 2016, 3/20/2016

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We review measuration, with the focus on:

• Areas of parallelogram and trapezium;
• Volume and surface area of a prism;
• Volume and surface area of a cylinder;
• Volume and surface area of a pyramid;
• Volume and surface area of a cone;
• Volume and surface area of a sphere;
• Length of an arc, area of a sector in a circle

Homework: from Page1, Page2, Page3:

#5- #18