CH2 Rounding

CH2 Rounding
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Slide 1: Slide
WiskundeMiddelbare schoolhavo, vwoLeerjaar 1

This lesson contains 23 slides, with interactive quizzes and text slides.

time-iconLesson duration is: 60 min

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CH2 Rounding

Slide 1 - Slide

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Start assignment
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Write down:
1) Something you learned, 2) something you still want to ask.

Slide 2 - Slide

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1) Something you learned
2) Something you want to ask

Slide 3 - Mind map

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Program:
  • Start assignment (5 minutes)
  • Homework check + quizizz (15 m)
  • Instruction (15 m)
  • Bettermarks (30m)
  • Assignment page 2 (20m)
Today I'll learn... 
...how to round whole numbers
...how to round decimal numbers
...to identify situaties in which rounding is worthwile

Slide 4 - Slide

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Quizizz & homework check
Quizizz: https://quizizz.com/admin/quiz/66f0044c2c152b63455ef191?section=collections&searchLocale=


Slide 5 - Slide

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Instruction: Rounding
  • When rounding, consider the digit to the ⁣right⁣ of the place you are rounding to.
  • 0, 1, 2, 3, 4 --> you round down
  • 5, 6, 7, 8, 9 --> you round up

  • Rounding to the nearest thousands:
  • 326 458⁣ ≈ ⁣326 000. ⁣


Slide 6 - Slide

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Round 908 to the nearest 10
A
900
B
910
C
920
D
901

Slide 7 - Quiz

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Round 764 to the nearest 100
A
700
B
770
C
704
D
800

Slide 8 - Quiz

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Round 614 to the nearest 10
A
610
B
620
C
600
D
630

Slide 9 - Quiz

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Round 1486 to the nearest 1000
A
1000
B
1400
C
1500
D
2000

Slide 10 - Quiz

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Round 235 to the nearest ten.
A
200
B
345
C
240
D
340

Slide 11 - Quiz

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Rounding (2): upper & lower bound

  • Given a rounded number, the range in which the original number can lie is given by an upper bound and a lower bound
  • The equator is approximately ⁣40 100 km⁣ long. What length in kilometers could it actually be?
  • 40 100⁣ has been rounded to the ⁣nearest hundred.
  • So 40050 is the lower bound and 40149 is the upper bound, all numbers from ⁣40 050⁣ to ⁣40 149⁣ are possible.
  • The length of the equator is between ⁣40 050 km⁣ (the lower bound) and ⁣40 149 km⁣ (the upper bound).




Slide 12 - Slide

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Rounding (3): decimal numbers
  • The same rules apply for rounding decimal numbers as for ⁣natural⁣ numbers.
  • Look at the place to the right of the one you need to round to.
  • If the digit there is ⁣0, 1, 2, 3 or 4⁣ you round ⁣down. ⁣
  • The digit in the place you want to round does not change. Rounding down makes the number ⁣smaller.
  • If the digit there is ⁣5, 6, 7, 8 or 9⁣ you round ⁣up. ⁣
  • The digit in the place you want to round increases by 1. Rounding up makes the number ⁣larger.


Slide 13 - Slide

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Round 23.07643 to thousandths
A
23.08
B
23.076
C
23.07
D
23.086

Slide 14 - Quiz

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Round 23.07643 to tenths
A
23.0
B
23.1
C
23.08
D
23.07

Slide 15 - Quiz

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Round 23.076496 to 5 decimal places
A
23.07649
B
23.07659
C
23.07650
D
23.07646

Slide 16 - Quiz

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Round 31.00456987 to thousandths
A
31.005
B
31.004
C
31.001
D
31.002

Slide 17 - Quiz

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Round 6.26427 to 2 decimal places.
A
6.25
B
6.26
C
6.27
D
6.3

Slide 18 - Quiz

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Round 6.26427 to 1 decimal place.
A
6
B
6.2
C
6.3
D
6.5

Slide 19 - Quiz

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Rounding (4): Everyday situations
  • It is ⁣not⁣ always a good idea to use the rounding rules in real situations. Sometimes this can have a bad result.
  • For example: repaper the walls of your room, 5.2 rolls becomes 6 instead of 5.

Slide 20 - Slide

For example: you want to repaper the walls of your room, you calculate you need 5.2 rolls of wallpaper. In this case you havo to round up to 6 rolls of wallpaper, otherwise you wouldn't be able to finish you entire room.
Bettermarks
Make: 5.1, 5.2, 5.3, 5.6, 5.9
Done? Check your weekplanner.

Slide 21 - Slide

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Assignment decimal numbers
  1. Check work of someone else 
  2. Make page 2 

Slide 22 - Slide

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Evaluation
Homework: 
Make: 5.1, 5.2, 5.3, 5.6, 5.9

Today I'll learn... 
...how to round whole numbers
...how to round decimal numbers
...to identify situaties in which rounding is worthwile

Slide 23 - Slide

For example: you want to repaper the walls of your room, you calculate you need 5.2 rolls of wallpaper. In this case you havo to round up to 6 rolls of wallpaper, otherwise you wouldn't be able to finish you entire room.