Working With Lengths Viki, Janina, Uli, Celina und Corbi Friday, 13th of March 2015.

Working With LengthsViki, Janina, Uli, Celina und Corbi

Friday, 13th of March 2015

Contents

• Introduction: Learning Objectives Uli

• Main 1: Adding, Subtracting, Multiplying and Dividing with Lengths Viki

• Main 2:Perimeters Janina

• Main 3:Word Problems Celina

• Review: Lessons learned Corbi

Working with lengths

Main 1: Addition and Subtraction

We will talk about working with lengths! Maybe you already know what I am going to „teach“ you but lets start…

•First of all you need to convert e.g. cmm

•No matter which calculation you have to do: Do it with the same unit!

•Then you just need to add and/or subtract like you do with normal numbers

Main 1: Multiplication and Division

Now, multiplying and dividing is almost the same:

•Convert e.g. m km

•Then just multiply and / or divide like you do with normal numbers!

I hope now you know how to do the four operations with lengths!


A Street is built and so far 24,849 m long. 3,46 m more are finished today! How long is the street now?

24,849

+ 3,46

28,309


A cat sits on a branch that is 2,55 m high. Ina is 1,42 m when she puts her arm up she comes 34 cm over her haid. She gets a ladder that is 70 cm tall. Can she help her cat?

Convert:

1,43 m = 143 cm 2,55 m = 255 cm

+ 34 cm

+ 70 cm

247 cm


Jenny has a Garden. It is 10 m long and 5 m wide! How big is her Garden?

10 x 5 = 50 m²

Note: If you multiply two length of different directions the result is m².


A 1,80 m long wood stick gets cut down into pieces of 45 cm. How much pieces do you get?

Convert: 1,80 cm = 180 cm

180 : 45 = 4

Main 2: Perimeter

• Janina will present this topic with the ‘‘White Boards‘‘

Main 3: Word Problems

• Question 1:

Mr. Greenbird lives in Coconut Grove Island and wants to build a fence around his garden, to protect his purple palm tree from wild animals.But, he wants to install a garden gate that is 127cm wide and plant a hedge with a length of 0.00393km at the property line (Grundstücksgrenze).

How many meters of fence does Mr. Greenbird need if each side of the garden is 4.13m long?


• Calculation method.



• Solution 1:

the perimeter of the garden is: 4 x 4.13m = 16.52m.

convert the garden gate in m: 127cm = 1.27m and the hedge in m: 0.00393km = 3.93m

add the fixed elements: 1.27m + 3.93m = 5.2m

subtract the fixed elements from the perimeter: 16.52 – 5.2m = 11.32m

Answer: Mr. Greenbird needs 11.32m of fence.



• Question 2:

Harry wants to build three picture frames. The lengths of these frames should be 180mm each and the width should be 13cm each. In the building supply store (Baumarkt), a ridge (Leiste) has a length of 2.40m. Calculate: 1. How many cm of ridge does he need to build 3 frames?

2. How many cm of the ridge(s) are left?



1. How many cm of a ridge does he need to build 3 frames?2. How many cm of the ridge(s) are left?


• Solution 2:

convert the length of a picture in cm: 180mm = 18cm

the perimeter of a picture is: 2 x 18cm + 2 x 13cm = 62cm

the total perimeter of all pictures is: 62cm x 3 = 186cm

convert the length of the ridge in cm: 2.4m = 240cm

subtract the total perimeter from the length of the ridge: 240cm – 186cm = 54cm

Answer: a) he needs 186cm of ridge and b) 54cm of the ridge are left.

1. How many cm of a ridge does he need to build 3 frames?2. How many cm of the ridge(s) are left?


• Question 3:

A square with a perimeter of 0.4 m has been cut in half. Both halfs were put next to each other to form a rectangle (see picture below).

How long is the perimeter of the rectangle in cm?

a) 32cm b) 40cm c) 44cm d) 48cm e) 50cm



How long is the perimeter of the rectangle in cm?Answer: ? a) 32cm b) 40cm c) 44cm d) 48cm e) 50cm


• Solution 3:

convert m in cm: 0.4m = 40cm

the side lenghts of the square is: 40cm : 4 = 10cm the perimeter of the rectangle is made up of 4 complete sites and of 2 half

sites: 4 x 10cm+ 2 x 5cm = 50cm

Answer: e) is correct - the perimeter of the rectangle is 50cm.

How long is the perimeter of the rectangle in cm?Answer: ? a) 32cm b) 40cm c) 44cm d) 48cm e) 50cm

Review: Lessons learned

• Corbi will present the review

• Uli & Corbi will hand out worksheets

Working With Lengths Viki, Janina, Uli, Celina und Corbi Friday, 13th of March 2015.

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