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Maths

Rounding and Significant Figures

Rounding

 

 

 

 

Round these numbers to one decimal place:

2.46

3.82

0.34

0.46

2.13

 

 

 

 

 

 

 

Round these numbers to two decimal places:

0.342

0.467

2.134

5.329

2.187

 

 

 

 

 

 

 

 

 

 

 

What are the rules for rounding?

Which numbers do you round up?

Which numbers do you round down?

Copy these sentences into your book and fill in the gaps with either up or down-

Numbers 0 --> 4 round _______

Numbers 5 --> 9 round _______

If the number is less than 5 you round_______

If the number is equal to 5 or greater you round_______

When N < 5 you round______

When N = 5 you round_____

N means number.

What does this symbol mean < ?

What does this symbol mean > ?

What does this symbol mean = ?

 

 

 

 

 

Using inequalities-

If you wanted to say that 5 is smaller than 8 you could write...

5 < 8

If you wanted to say that 8 is bigger than 5 you could write...

8 > 5

A way to remember it-The crocodiles mouth always eats the larger number

The larger side points to the larger number and the smaller side points towards the smaller number.

> means bigger than

< means smaller than

Write these sentences using inequalities-

10 is bigger than 5

7 is bigger than 2

8 is smaller than 13

5 is smaller than 6

Now write these inequalities as sentences-

5 > 3

3 < 5

9 > 5

7 < 22

 

Significant Figures

In any number the first significant figure is the first figure which is not a zero.

Round these numbers to one significant figure-

7166

20874

314837

Round these numbers to two significant figures-

3660

595.19

0.284

 

 

 

 

 

Look at the my maths lessons on rounding and significant figures.

www.mymaths.co.uk

Significant figures -

http://www.mymaths.co.uk/tasks/library/loadLesson.asp?title=accuracy/significantfigures&taskID=1005

Rounding -

http://www.mymaths.co.uk/tasks/library/loadLesson.asp?title=estimating/estimatingGold&taskID=1373

 

 

 

Upper and Lower bounds-

Take a quick look at the my maths lessons for upper and lower boounds to give you a headstart on our next lesson. I do not expect you to understand it all!

http://www.mymaths.co.uk/tasks/library/loadLesson.asp?title=accuracy/uplowboundsEasy&taskID=1067

http://www.mymaths.co.uk/tasks/library/loadLesson.asp?title=accuracy/uplowbounds&taskID=1006

Homework

Go to www.mymaths.co.uk

log on as your school

In the library click number then estimating and accuracy.

Do the homework tasks for:

solving problems by rounding

significant figures

And upper and lower bounds part 1

When clicked you will be asked if you want to complete the lesson or homework task. Select homework task but if you are unsure please go back through the lesson. It will then ask for your personal login and password. This is how i know if you have done it, how well you did and how long it took you. It shouldn't take more than 30 minutes.

Don't worry if you cannot complete the upper and lower bounds homework very well but please at least try. Do workings in book but also fill in your answers online and make sure you click mark it so i see how you did! I will be taking in your books and expect workings. You can start these tasks in class if you finish the other work early.

Your teacher should now run through how to access the my maths homework. You should be shown on the board and get an idea of what the web-site looks like and have an idea of how to access everything.

Your teacher will also now give you your personal logins and passwords.

Any queastions about my maths?

Please try to access it tonight or as soon as possible and go and see your teacher if you do not understand the work or cannot get onto my maths. If you would like to check if i have received it or not please come and see me about that BEFORE it is due in!!

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