1718 WB1Z CH10 Lesson 5

• Wiskunde
• Middelbare school
• vwo
• Leerjaar 1

Which exercises/theory should I discuss on the board?

Rounding up or down?

The formula                                       is given.
Take                          and solve the corresponding equation, round your answer to a whole number.

What is the rounded (to a whole number) solution to the equation
4c + 8 = 21?

1. 3
2. 4
3. 5
4. 6

Rounding up or down?

The formula                                       is given.
Take                          and solve the corresponding equation, round your answer to a whole number.

Rounding up or down?

In the formula                        
c stands for number of cars and n stands for number of athletes. The formula is about an athletics team that has a small bus that can take 8 athletes to an activity and also has several cars that can take 4 athletes to the activity.
21 athletes need to go to an activity, how many cars are needed?                               

How many cars are needed?

1. 3
2. 4
3. 5
4. 6

Rounding up or down?

3 cars will not be enough
So the answer is 4 cars. We ignore the normal rules for rounding off, because they don't work for this situation.

Rounding up or down?

If an exercise is about a realistic situation, you have to decide if you should follow the normal rules for rounding off or not.

Exact or an approximation

Some solutions to an equation are a fraction that cannot be written as a decimal number.
Example:

Exact or an approximation

The solution                      is called the exact solution
The solution                      is an approximation, accurate to two decimal places.

What is the EXACT solution to the equation 14a + 5 = 9

1. a=4
2. a=0.29
3. a=3.5
4. a=​7​​2​​

Homework Friday

Make and correct the exercises from the studyplanner up to and including §10.5: 30, 31, 32, 33, 34, 35