# 1718 WB1Y CH10 Lesson 6

Which exercises/theory should I discuss on the board?
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Slide 1: Mind map
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This lesson contains 12 slides, with interactive quizzes and text slides.

Lesson duration is: 50 min

## Items in this lesson

Which exercises/theory should I discuss on the board?

#### Slide 1 -Mind map

What is 5.384921 rounded to three decimal places?
A
5.38
B
5.384
C
5.385
D
5.395

#### Slide 2 -Quiz

5.384921
The 4th decimal is a 9, this means the 3rd decimal should increase by 1.
5.385

#### Slide 3 -Slide

What is 0.19523 rounded to two decimal places?
A
0.19
B
0.20
C
0.2
D
0.30

#### Slide 4 -Quiz

0.19523
The 3rd decimal is a 5, this means the 2nd decimal should increase by 1. Since this makes 10, the 1st decimal is increased by 1. A 0 is written in the 2nd decimal place, because you have to have two decimal places.
0.20

#### Slide 5 -Slide

Solve the equation. Give your answer as an approximation accurate to 2 decimal places.
10 - 3a = 15
A
132
B
132
C
1.67
D
-1.67

#### Slide 6 -Quiz

Notation                                                     What you might think
10 - 3a = 15                                                 10 + 5  = 15, so 10 - -5 = 15
3a = -5                                                          then 3a = -5
3 x a = -5, then a = -5 : 3
-5 : 3 in my calculator gives
1.666666667, so rounded off
to two decimal places is 1.67
a=351.67

#### Slide 7 -Slide

Solve the equation.
3.5a + 8 = 9
A
0.285714286
B
1
C
3.51
D
72

#### Slide 8 -Quiz

Notation                                     What you might think
3.5a + 8 = 9                               9 - 8 = 1, so 1 + 8 = 9
3.5a = 1                                      then 3.5a = 1
3.5 x a = 1, then a = 1 : 3.5
you cannot have a fraction with a
decimal number, so multiply the
numerator and denominator with 2.
a=3.51=72

#### Slide 9 -Slide

What is the first step when making a formula from a graph?
A
shorten the formula
B
C
find the start value
D
make a table

#### Slide 10 -Quiz

Graph -> Formula
1) Make a table (horizontal axis top row, vertical axis bottom row) and fill in some easy to read off points on the graph (grid points).
2) Calculate the gradient (steps in the bottom row divided by the steps in the top row)
3) Find the start value (value in the bottom row when the value in the top row is 0)
4) Make a formula:
start value +/- gradient x top row variable = bottom row variable

#### Slide 11 -Slide

Homework Monday
Make and correct all exercises from the studyplanner up to and including §10.6:
36, 37, 38, 39, 40, 41, 42