Chapter 7 Word formulas

Chapter 7 Word formulas
Formulas are used a lot in Mathematics.

A formula is a rule that describes how to perform a particular calculation.
1 / 25
next
Slide 1: Slide
WiskundeMiddelbare schoolhavoLeerjaar 1

This lesson contains 25 slides, with text slides.

Items in this lesson

Chapter 7 Word formulas
Formulas are used a lot in Mathematics.

A formula is a rule that describes how to perform a particular calculation.

Slide 1 - Slide

Slide 2 - Slide

7.1 Make a formula from a description
Work out how to calculate something by trying a few times and seeing how you do it.
Put your answers in a table.

Slide 3 - Slide

Slide 4 - Slide

S4 on page 229
Homework : exercises 1 t/m 8

Slide 5 - Slide

7.2 Making a graph from a formula
You first need to make a table
The top row of the table will be the horizontal axis .
and the bottom row will be the vertical axis.
Remember to use equal size steps on both axes.
Fill values from top row into the formula to calculate the values for the bottom row.
Now you have values to plot (draw) your graph.

Slide 6 - Slide

Formula
Table
Graph

Slide 7 - Slide

Slide 8 - Slide

Slide 9 - Slide

S5 on page 230
Homework: exercises 9 t/m 11

Slide 10 - Slide

7.3 Linear formulas
Linear sounds like the word line.
In this chapter we are looking at linear graphs which are straight line graphs. 
Every time the same amount is added or subtracted.
Sometimes the straight line goes through (0,0) the origin and sometimes there is a starting amount which means the line starts higher up the vertical axis.

Slide 11 - Slide

Slide 12 - Slide

To see if a graph is rising or falling
Rising means going up or getting bigger.
This is when you add an amount every time.

Falling means going down or becoming smaller.
This happens when you take an amount away (subtract) every time.

Slide 13 - Slide

Slide 14 - Slide

S6 on page 230
Homework: 17 t/m 24

Slide 15 - Slide

7.4 Making a Formula from a graph.
You first need to make a table
Then you can see the starting amount and work out how much it increases or decreases every time.
e.g. Amount = starting amount + gradient x time
Gradient = how much goes up/how much across

Slide 16 - Slide

Slide 17 - Slide

Slide 18 - Slide

To see if a graph is rising or falling

Slide 19 - Slide

S8 on page 231
Homework : ex 25 t/m 31

Slide 20 - Slide

7.5 Comparing Graphs 

Slide 21 - Slide

Filling values into formula
If we fill a value into the formula we can calculate the answer.
Sometimes we use this to see if the answer they give is correct.
Sometimes we do it to see if the answer is same as the answer we get from another formula.

Slide 22 - Slide

e.g To see if point (50,75) is on a line?
Fill value 50 into formula and it should give answer 75.
If it gives a different answer then not on the graph (line).

Slide 23 - Slide

e.g. To compare two different formulas
Make a table with values.
Underneath calculate the answers using one formula.
Then underneath that calculate the answers using the other formula.
Now you can see when the two answers are equal and/or which one is bigger or smaller for a certain value.

Slide 24 - Slide

Any questions?

Slide 25 - Slide