1TTO §9.2 Adding negative numbers 20-21

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

We're gonna do some adding ...

with Positive and especially Negative Numbers!

As usual...

this LessonUp marches through the most

important aspects of the whole paragraph,

making it much easier to deal with it yourself, afterwards!

We're gonna do several exercises together, so: less homework.

A cauldron (ketel) 

+ she puts in HOT BLOCKS and also

+ COLD BLOCKS 

+ to control the temperature

+ (every Blocks represents one degree!)

+ if there are just as many Hot blocks as there are Cold Blocks,

+ then the temperature is 0 degrees.

The temperature is 0 degrees.
If added 5 cold blocks. (1 block = 1 degree)
What's the new temperature?

1. 5
2. +5
3. -5

There are 13 cold blocks and 7 hot blocks in the cauldron.
What is the temperature?

1. -6
2. 6
3. 20
4. -20

Explanation:

13 cold blocks correspond to -13 degrees

7 hot blocks correspond to +7 degrees,

so the calculation is:

-13 + 7 = -6

In the next slide...

+ many changes in temperature come up!

+ your teacher will tackle the first line

+ then all think about the next line

+ one of you will get the turn!

+ and so on with the 3rd line, etcetera

Exercise 10

Next slide ...

+ offers us a huge table again

+ your teacher will take care of the first line again

+ then some of you get the turn to tackle the next lines

+ maybe youthink it's all still very simple(?)

+ beware: next lesson the Witch will also TAKE OUT Hot en Cold Blocks;

+ so it's important to understand the ADDING of Blocks first! 

Not really surprising, this, but good to realise!

Think about the following TASK:

(This is a snapshot from exercise 14)

Solution:

-35 + 40 = 5

Finally:

        An example of this follows!

Now think about this one for a while!

                               Next slide will provide us with the Solution!

Using the number line, you that you have to

add up the length from 13        till 0,

and the length from 0 to -2.5 !

That is:   13       +   2         =     15 

However we go from positief to negative,

so we subtract. The answer is:  -15.9

​5​​2​​

​5​​2​​

​10​​5​​

​10​​9​​

Homework time

Make of 9.2:   10, 11, 12, S13, 13, 15