Adding and subtracting/multiplying fractions

Good morning!

Schedule:

Learning goals
Last time
Adding/subtracting fractions
Multiplying fractions
Work/practice

1 / 20

Slide 1: Slide

WiskundeMiddelbare schoolvwoLeerjaar 2

This lesson contains 20 slides, with interactive quizzes and text slides.

Items in this lesson

Good morning!

Schedule:

Learning goals
Last time
Adding/subtracting fractions
Multiplying fractions
Work/practice

Slide 1 - Slide

Learning goals

At the end of this lesson I can:

add any fraction to another fraction
subtract any fraction from another fraction
Do multiplications with proper fractions
Do multiplications with mixed numbers and improper fractions

Slide 2 - Slide

Last time

Slide 3 - Mind map

\frac{​ 1 ​ ​}{​ 2 ​} + \frac{​ 3 ​ ​}{​ 6 ​} =

\frac{​ 4 ​ ​}{​ 8 ​}

\frac{​ 3 ​ ​}{​ 1 2 ​}

\frac{​ 2 ​ ​}{​ 2 ​}

Slide 4 - Quiz

Equal fractions

\frac{​ 1 ​ ​}{​ 2 ​} = \frac{​ 3 ​ ​}{​ 6 ​}

Slide 5 - Slide

When am I allowed to add or subtract fractions?

Slide 6 - Open question

Adding/subtracting fractions

Same denominator!!

\frac{​ 2 ​ ​}{​ 6 ​} + \frac{​ 1 ​ ​}{​ 6 ​} =

\frac{​ 1 ​ ​}{​ 3 ​} + \frac{​ 2 ​ ​}{​ 9 ​} =

\frac{​ 5 ​ ​}{​ 7 ​} - \frac{​ 3 ​ ​}{​ 8 ​} =

Slide 7 - Slide

Multiplying fractions

Slide 8 - Slide

Multiplying fractions

\frac{​ 1 ​ ​}{​ 3 ​} \cdot \frac{​ 2 ​ ​}{​ 5 ​} = \frac{​ 1 \cdot 2 ​ ​}{​ 3 \cdot 5 ​} = \frac{​ 2 ​ ​}{​ 1 5 ​}

Numerator x numerator

Denominator x denominator

Slide 9 - Slide

Mixed numbers/whole numbers?

Slide 10 - Slide

What is the difference between multiplying and adding/subtracting fraction?

Slide 11 - Open question

Adding fractions

How can thinking about the context of a problem help you in

understanding the situation and what the question is asking you to solve? How can this

help you to determine a way to solve this problem?

Discuss with neighbour (2min)

Slide 12 - Slide

A school uses part of a field to create a rectangular area for the PTA carnival. They will partition the field so there are areas for games, food, and prizes. If of the field is for prizes, and of the field is for games, what fraction of the field is remaining for food?

How can the context/story of the problem help you solve it? what strategy would you use?

Discuss (5 min)

\frac{​ 1 ​ ​}{​ 2 ​}

\frac{​ 1 ​ ​}{​ 6 ​}

Slide 13 - Slide

Think of a reasonable estimate for the answer to the question. Write this down on your mini-whiteboard.

Discuss (5 min)

\frac{​ 1 ​ ​}{​ 2 ​}

\frac{​ 1 ​ ​}{​ 6 ​}

Slide 14 - Slide

What do you think?

a. The answer is less than 1.

b. The answer is more than

c. The answer is less than

d. The answer is more than 0.

e. The answer is closer to 0 than

\frac{​ 1 ​ ​}{​ 2 ​}

\frac{​ 1 ​ ​}{​ 2 ​}

\frac{​ 1 ​ ​}{​ 2 ​}

Slide 15 - Slide

Now find the exact answer to the problem:

Slide 16 - Open question

Slide 17 - Slide

Adding/subtracting fractions

You changed 1/2 into 3/6

When you add 2 fractions you need to change them to make the denominators equal

https://www.geogebra.org/m/d4sq3jzx

Slide 18 - Slide

(Home)work

Worksheet on ManageBac: 1-10

p. 113 : 5H 1bfjcgk, 2aei, 3, 4be, 5

Finished? Challenge worksheet!

MyiMaths:

- adding and subtracting fractions

Slide 19 - Slide

Challenge

Slide 20 - Slide