# 2.10 Fractions - 06

 Page 1 / 1

## Memorandum

14. a) denominator

b) common denominator

c) multiple

d) tellers

e) number

f) fractions

g) improper fractions

h) simplify

15.2 a)

= $\frac{\text{12}}{\text{21}}$ + $\frac{\text{14}}{\text{21}}$

= $\frac{\text{26}}{\text{21}}$

= 1 $\frac{5}{\text{21}}$

b)

= $\frac{5}{\text{10}}$ + $\frac{6}{\text{10}}$

= $\frac{\text{11}}{\text{10}}$

= 1 $\frac{1}{\text{10}}$

c)

= $\frac{\text{36}}{\text{45}}$ - $\frac{\text{25}}{\text{45}}$

= $\frac{\text{11}}{\text{45}}$

d)

= $\frac{4}{6}$ - $\frac{3}{6}$

= $\frac{1}{6}$

16.

a)

= $\text{11}\frac{2}{3}$ + $\frac{1}{7}$

= $\text{11}\frac{\text{14}}{\text{21}}$ + $\frac{3}{\text{21}}$

p = $\text{11}\frac{\text{17}}{\text{21}}$

b)

= $3\frac{1}{4}-\frac{1}{9}$

= 3 $\frac{9}{\text{36}}-\frac{4}{\text{36}}$

t = 3 $\frac{5}{\text{36}}$

= 6 $\frac{3}{4}$ – (3 $\frac{1}{2}$ + 1 $\frac{2}{3}$ )

= 6 $\frac{3}{4}$ – 3 $\frac{3}{6}$ + $\frac{4}{6}$

= 6 $\frac{3}{4}$ – 4 $\frac{1}{6}$

= 2 $\frac{9}{\text{12}}$ - $\frac{2}{\text{12}}$

g = 2 $\frac{7}{\text{12}}$

d)

= 9 $\frac{7}{8}$ - (4 $\frac{9}{\text{12}}$ + $\frac{8}{\text{12}}$ )

= 9 $\frac{7}{8}$ - 5 $\frac{5}{\text{12}}$

= 4 $\frac{7}{8}$ - $\frac{5}{\text{12}}$

= 4 $\frac{\text{21}}{\text{24}}$ - $\frac{\text{10}}{\text{24}}$

v = 4 $\frac{\text{11}}{\text{24}}$

## Activity: addition and subtraction of fractions [lo 1.7.3]

14. Addition and subtraction of fractions

LET US REVISE.

The answers to the following questions are hidden below.

Circle them when you find them and then complete the sentences.

 a b t t t s o n k o f m n d e n o m i n a t o r y u e d e l u o a e n r a j m n k l l l e a m d o c p e o h a e t m l e i n t o r m m v r i e d r g e i o a i n i s p r f e s g o g t n s u x l m g p t t n h o a e q k e l v o l e s t r t d e f s h j r k l e e s o q w e r t y p y o l u h r s d a z d o m u b g e s s i m p l i f i e d e l h

a) We can only add or subtract fractions if the.................................................. are the same.

b) If the denominators differ, we must find .................................................. fractions with the same denominators.

c) We can find the common denominator easily by using ..................................................

d) We only add the.................................................. together.

e) The .................................................. stays unchanged when we add or subtract.

f) When we add mixed numbers together, we first add the natural numbers and then

the ..................................................

g) When we subtract mixed numbers, we can first change them to ................................................. fractions.

h) Answers must always be .................................................. as far as possible.

15.1 Do you still remember?

When we add or subtract e.g. one third ( $\frac{1}{3}$ ) + four fifths ( $\frac{4}{5}$ ) or five sixths ( $\frac{5}{6}$ ) – two nineths ( $\frac{2}{9}$ ) we must first make the DENOMINATORS the same. To do this we must look for the Lowest Common Multiple (LCM) .

If we want the LCM of 3 and 5 we can work as follows:

3: 3 ; 6 ; 9 ; 12 ; 15 ; 18 ; 21 ; etc.

5: 5 ; 10 ; 15 ; 20 ; 25 ; etc.

 Thus we change both denominators to 15:
 1 × 5 3 × 5
=
 5 15
en
 4 × 3 5 × 3
=
 12 15

Thus: $\begin{array}{}\frac{1}{3}+\frac{4}{5}\\ \frac{5}{\text{15}}+\frac{\text{12}}{\text{15}}\\ \frac{\text{17}}{\text{15}}\\ 1\frac{2}{\text{15}}\end{array}$

15.2 Calculate the following:

a) $x=\frac{4}{7}+\frac{2}{3}$

___________________________________________________

___________________________________________________

___________________________________________________

___________________________________________________

b) $y=\frac{1}{2}+\frac{3}{5}$

___________________________________________________

___________________________________________________

___________________________________________________

___________________________________________________

c) $d=\frac{4}{5}-\frac{5}{9}$

___________________________________________________

___________________________________________________

___________________________________________________

___________________________________________________

d) $k=\frac{2}{3}-\frac{1}{2}$

___________________________________________________

___________________________________________________

___________________________________________________

___________________________________________________

16. Work together with a friend and calculate:

a) $p=7\frac{2}{3}+4\frac{1}{7}$

___________________________________________________

___________________________________________________

___________________________________________________

___________________________________________________

b) $t=5\frac{1}{4}-2\frac{1}{9}$

___________________________________________________

___________________________________________________

___________________________________________________

___________________________________________________

c) $g=6\frac{3}{4}-\left(2\frac{1}{2}+1\frac{2}{3}\right)$

___________________________________________________

___________________________________________________

___________________________________________________

___________________________________________________

d) $v=9\frac{7}{8}-\left(3\frac{3}{4}+1\frac{2}{3}\right)$

___________________________________________________

___________________________________________________

___________________________________________________

___________________________________________________

17. CHALLENGE!

Divide into groups of three. Complete the following table by filling in the number of hours you spent doing homework last week:

 NAME Mon Tues Wed Thur Fri e.g Nomsa $1\frac{1}{2}$ $2\frac{1}{4}$ $3\frac{3}{4}$ $1\frac{1}{2}$ $\frac{1}{2}$ 1. ............................................... ............ ............ ............ ............ ............ 2. ............................................... ............ ............ ............ ............ ............ 3. ............................................... ............ ............ ............ ............ ............

a) How many hours did each member of the group spend on homework last week?

1. _________________________________

2. _________________________________

3. _________________________________

b) Who spent the most time on homework? _______________________________

c) Who learnt the least? _________________________________

d) Calculate the difference between b en c’s answers.

___________________________________________________

___________________________________________________

___________________________________________________

___________________________________________________

## Assessment

Learning Outcome 1: The learner will be able to recognise, describe and represent numbers and their relationships, and to count, estimate, calculate and check with competence and confidence in solving problems.

Assessment Standard 1.7: We know this when the learner estimates and calculates by selecting and using operations appropriate to solving problems that involve:

1.7.3: addition, subtraction and multiplication of common fractions.

anyone know any internet site where one can find nanotechnology papers?
research.net
kanaga
Introduction about quantum dots in nanotechnology
what does nano mean?
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
absolutely yes
Daniel
how to know photocatalytic properties of tio2 nanoparticles...what to do now
it is a goid question and i want to know the answer as well
Maciej
Abigail
for teaching engĺish at school how nano technology help us
Anassong
Do somebody tell me a best nano engineering book for beginners?
there is no specific books for beginners but there is book called principle of nanotechnology
NANO
what is fullerene does it is used to make bukky balls
are you nano engineer ?
s.
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
Tarell
what is the actual application of fullerenes nowadays?
Damian
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
Tarell
what is the Synthesis, properties,and applications of carbon nano chemistry
Mostly, they use nano carbon for electronics and for materials to be strengthened.
Virgil
is Bucky paper clear?
CYNTHIA
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
NANO
so some one know about replacing silicon atom with phosphorous in semiconductors device?
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Harper
Do you know which machine is used to that process?
s.
how to fabricate graphene ink ?
for screen printed electrodes ?
SUYASH
What is lattice structure?
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
On having this app for quite a bit time, Haven't realised there's a chat room in it.
Cied
what is biological synthesis of nanoparticles
what's the easiest and fastest way to the synthesize AgNP?
China
Cied
types of nano material
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
what is the k.e before it land
Yasmin
what is the function of carbon nanotubes?
Cesar
I'm interested in nanotube
Uday
what is nanomaterials​ and their applications of sensors.
how did you get the value of 2000N.What calculations are needed to arrive at it
Privacy Information Security Software Version 1.1a
Good
Berger describes sociologists as concerned with
Got questions? Join the online conversation and get instant answers!