1TH/Vwo §7.3 Decimal numbers

• Wiskunde
• Middelbare school
• havo, vwo
• Leerjaar 1

§7.3 Decimal numbers

You all know about decimal numbers.

It is similar to fractions, but now written with a point and not with a fraction symbol.

So:   0.5    instead of   

​2​​1​​

The same 'order of operations' as you learnt applies now!

And you can take the

+ sum

+ difference

+ product and 

+ quotient  again!

+ above all the brackets 'rule' again, having top priority!

6.6 - 4 x 1.5 =

1. 6
2. 3.9
3. -0.6
4. 0.6

explanation:

First comes X  and only then we do  -,  so:

6.6 - 4 x 1.5 =

6.6 - 6 = 0.6

5.6 x 0.01 = ....

1. 5600
2. 0.56
3. 0.056
4. 560

explanation:

multiplying by 0.01 is the same as taking 

of that number, or placing the decimal point 2 places to the left, so:

5.6 x 0.01 = 0.056

 

​100​​1​​

Finally a remark about exercise 25:

In 25 the calculations have become that complicated, that it is important to work them out in a few steps!

Look at the following example.

This becomes pretty tricky, reason for us to work it out on paper like this:

0.1 x 14 x 100 = 1.4 x 100 = 140

So first the brackets, then the square and finally the 2 multiplications!

One more TASK:

      4.2 + (      - 28) =

+ Copy this task in your Notebook

+ write down the CALCULATION and only then the ANSWER

+ take a picture and 

+ send it in in the FOTOVRAAG!

8​2​​

VWO task
Send in a pic of your CALCULATION!

4.2+(8​2​​−28)=

Explanation:

4.2 + (      - 28)  =               Brackets first.

4.2 + (64 - 28) =               Between the brackets: the power first.

4.2 + 36  =   

40.2                        

8​2​​

Homework time

do § 7.3 now 

you may skip:  18  and  19

however, don't forget to WORK OUT exercise 25, so don't 

only give the answers!