1718 WB1Z CH4+8 Lesson 3

• Wiskunde
• Middelbare school
• vwo
• Leerjaar 1

Which homework exercises would you like for me to discuss on the board?
(1 exercise per answer, you can give multiple answers)

Recap: Order of Operations
Calculate and show steps
25 - 18 : 3 + 2 x (7-3) =

Recap: Adding and subtracting fractions

​8​​7​​+​3​​2​​−​24​​3​​=

1. 1​3​​2​​
2. 1​12​​5​​
3. ​35​​6​​
4. none of the above

B.

1​12​​5​​

Recap: Multiplying fractions
(the . means x)

1​5​​3​​⋅​3​​2​​=

1. 1​4​​1​​
2. 1​15​​6​​
3. 1​5​​2​​
4. none of the above

D. none of the above

Language

vijf keer vier is twintig                    five times four equals twenty
vermenigvuldigen (x)                     multiplying
tien gedeeld door vijf is twee     ten divided by five equals two
delen (:)                                                 division
vijf plus vier is negen                      five plus four equals nine
optellen                                                addition
vijf min drie is twee                         five minus three equals two
aftrekken                                             subtraction                                      
 

Language

vijf in het kwadraat is vijfentwintig      five squared equals twentyfive
kwadrateren                                                    squaring

breuk                                                                 fraction
teller                                                                   numerator
noemer                                                             denominator
drie vijfde                                                        three fifth

​5​​3​​

Squaring fractions

You can also square fractions. When we write this down, you put brackets around the fraction you are squaring.

Squaring fractions

You can also square fractions. When we write this down, you put brackets around the fraction you are squaring.

Order of operations

When calculating with fractions, you have to follow the order of operations.
1. Calculate what is within brackets
2. Calculate squares
3. Multiply and divide from left to right
4. Add and subtract from left to right

Decimal numbers

When multiplying with 10, 100, 1000, but also 0.1, 0.01, 0.001, etc, you can notice a pattern.
12 x 1 = 12                                                12 x 1 = 12
12 x 10 = 120                                          12 x 0.1 = 1.2
12 x 100 = 1200                                     12 x 0.01 = 0.12
12 x 1000 = 12 000                               12 x 0.001 = 0.012
12 x 10 000 =  120 000                       12 x 0.0001 = 0.0012
You keep adding one zero.           You keep moving the decimal point to the left

48 x 0.0001 =

Fractions -> Decimal numbers

You can write fractions as decimal numbers.

Fractions -> Decimal numbers

If you can write a fraction with a denominator 10, 100, 1000, etc, you can turn the fraction into a decimal number, by moving the decimal point in the numerator.

Write as a decimal number

​25​​8​​

Fractions -> Decimal numbers

Some fractions cannot be written as decimal numbers.
Example:




Not the exact same result, therefore it is not exactly 0.17

Homework Friday

Make and correct from §4.3 and §4.4:
22, 24, 25, 28, 30, 32, 33

 
correcting your homework is part of the homework!