1.2 Approximating numbers

• Wiskunde
• WO
• Studiejaar 4

Good morning!

Schedule: 

• Learning goals
• Homework questions
• Rounding quiz
• Math is cool/what does it mean to be exact 
• Homework

Learning goals 

At the end of this lessons I can:

• Round to different degrees of accuracy 
• Represent number in a different form to be more exact

Homework questions

Please take 5 min and see if you can answer the questions on the Padlet. 

Any unanswered questions I will discuss on the board. 

It takes 0.0000033356 seconds for light to travel 1 km. Round this number to 3 significant figures.

round π to 4 decimal places
π ≈ 3.1415926535

Round π to the nearest hundredth.
π ≈ 3.1415926535

is 0.999999999...
a rational or irrational number?

A rational number

An irrational number

What does it mean to be exact?

 0.999999... = 1 

What does it mean to be exact?

First, if x = 0.9999999...

calculate: 

10x = 

9x =

Remember 10x - x = 9x

What does it mean to be exact?

x = 0.99999999... and 9x = 9

So, is 0.999999... rational or irrational? 

What does it mean to be exact 

Some numbers might appear or act a certain way, but can be rewritten to act or appear another way. 

We can represent some numbers a certain way to be more exact. 

Ex. 

= 

√​3​​​

2.23606797749978969...

MyiMaths login

1. Go to MyiMaths.com

2. 

3.

School username: international 45 

School password: triangle89

Write this in your notebook

Homework

MyiMaths: 

- Estimating calculations

- Rounding decimals

- Significant figures