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TES: The largest network of teachers in the world

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31 March work:a) a loss of $6.4 million b) a temperature increase of 6oC

c) a stock loss of 4 points d) 2.4 km above sea level

a) 16 b) -18 c) 0.7 d) 4 e) -2 f) 1.1 g) -0.3 h) -2.7

a) All whole numbers are rational numbers

b) 0 is not a rational number

c) All rational numbers are negative

d) All mixed numbers are rational numbers

e) All integers are rational numbers

a) b) c) d) e)

a) b) - c) d) -1 e)

a) a rational number less than -1 with a denominator of 6

b) a mixed number between -3 and -4

c) a rational number, not in lowest terms, with a numerator of -12

30 March work:Wallwisher: This is a website where you can add your thoughts and discussions. Go to these 2 walls below and write notes on the wall about everything you know (and the things you want to find out) about consecutive integers and standard form.

http://www.wallwisher.com/wall/consecutive

http://www.wallwisher.com/wall/standard

ePortfolios:

1. Your learning log should be completed with your own reflections up to Week 9

2. Your problem solving movie with reflections should be on your problem solving page

Now put your wallwishers onto your eportfolios:

1. Go to the wall where you have put your sticky notes

2. Under 'Do more' click Embed.

3. Copy the embed code.

4. Go to your Learning Log page of your ePortfolio. Click edit.

5. Make sure the cursor is underneath your Learning Log chart.

6. Click the yellow button on the top row of the editor 'insert html'

7. Paste the code into the box and save.

8. Do this for both your walls.

WORK FOR FAST FINISHERS:

A number in standard form (or standard index form) has the following formula:

a × 10ⁿwhere

ais a number between 1 and 10, andnis the amount of times you have to multiplyato give you the original number.Standard form is a way of writing down very large numbers or very small number in a shorter way, so that we can save time when writing down numbers.

In the following examples we are only looking at large numbers.

Example 1Write down 4000 in standard form.

Example 2Write down 370,000 in standard form.

Example 3Write down 87,500,000 in standard form.

Example 4Write 7,984,566 in standard index form. Write the answer to 3 significant figures.

## Estimating by rounding to 1 significant figure (estimation)

The easiest way to estimate in math is by rounding your numbers off to 1 significant figure. 1 significant figure is the first number from the left of the number (ignoring all the zeros from the left of the number - not the zeros between). Use a wavy equal sign for your approximations.Example 1Find an estimate to 45.3 + 123.8.

First of all round both of your numbers off to 1 significant figure.

45.3 ≈ 50 (this is like rounding off to the nearest 10)

123.8 ≈ 100 (this is like rounding off to the nearest 100)

Now all we need to do now is add up our two rounded off answers.

So 50 + 100 =150

So our estimate is 150.

Example 2Estimate (0.7+32.3) × 6.4

Example 3Estimate (44.8 + 36.3)/(7.2 – 3.1).

Learning about significant figures:

In 64,492 , 6 is the first significant figure.(sig.fig.) When we round off 64,492 to two sig. figs, that means in the answer we should have two non zero figures.The third figure(which is 4) is less than 5, so we drop them to zeros.Let's round off 64,492 to:(a)

1significant figurewhich is 60,000(b)

2significant figureswhich is 64,000(c)

3significant figureswhich is 64,500(d)

4significant figureswhich is 64,490(e)

5significant figureswhich is 64,492The accuracy of the answer will depend on the number of significant figures.The answer will be more accurate, if it is given to a higher number of significant figures.64,492 is the most accurate answer and it is given to 5 sig. figs.* The trailing zeros in a whole number are not significant.There are used to keep the other figures in there correct places.

eg. 64000 6 and 4 are significant not the zeros.

- The leading zeros in a decimal are not significant. There are used to keep the other figures in there correct places.

eg. 0.000054 , only 5 and 4 are significant.*The zeros between the figures are significant.eg. 30.05 each figure is significant. There are 4 sig.figs.

The last zero in a decimal is significant.eg. 3.20each figure is significant. There are

3sig.figs.

eg. 0.50, 5 and last zero are significant.There are

2 sigfigs