# 3.4 Adding and subtracting of decimal fractions

 Page 1 / 1

## Memorandum

17.2 a) 999,955

1. 802,383
2. 115,749
3. 420,799

18. 0,1818181

0,8181818

0,9999999

Above-mentioned are repetitive fractions

Rounded off, the answer is 1.

19.

a) 1

b) 3,3

c) 0,67

d) 4,3

e) 6,4

f) 2,7

g) 3,4

h) 1,25

i) 1,05

j) 6,7

k) 2,98

l) 1,12

m) 5

n) 8,6

o) 8,2

Leaner Section

## Activity: adding and subtracting of decimal fractions [lo 1.7.4]

17. ADDING AND SUBTRACTING OF DECIMAL FRACTIONS:

17.1 Do you still remember?

It is very easy to add and subtract decimal fractions. We do it in exactly

the same way that we would add and subtract whole numbers.

Just be certain that you write:

• the tenths in the tenths column.
• the hundredths in the hundredths column.
• the thousandths in the thousandths column.

17.2 Calculate:

a) n = 284,523 + 715,432

b) d = 476,897 + 325,486

c) k = 532,298 – 416,549

d) b = 785,361 – 364,562

18. BRAIN-TEASER!

• Write two elevenths as a decimal fraction. Then write nine elevenths as a decimal fraction. Add the two answers together.

…………………………………………………………………………………………..

…………………………………………………………………………………………..

• You already know that 2 elevenths plus 9 elevenths = 11 elevenths = one !
• How do you explain the above answer?

…………………………………………………………………………………………..

…………………………………………………………………………………………..

19. Let us see how you do in the following mental test.

a) 0,6 + 0,4 = .................

b) 2,4 + 0,9 = .................

c) 0,27 + 0,4 = .................

d) 5 – 0,7 = .................

e) 3,8 + 2,6 = .................

f) 3,2 – 0,5 = .................

g) 3,45 – 0,05 = .................

h) 3,45 – 2,2 = .................

i) 3,45 – 2,4 = .................

j) 2,65 + 4,05 = .................

k) 4 – 1,02 = .................

l) 0,39 + 0,73 = .................

m) 3,25 + 1,75 = .................

n) 4,9 + 3,7 = .................

o) 12 – 3,8 = .................

• Complete by ticking the applicable block:
 MYMARKS
 IMPROVED GOT THE SAME RESULT DID WORSE
when I compare my results with the results of the previous mental test.

## 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:

1.7.4 addition, subtraction and multiplication of positive decimals to at least 2 decimal places.

#### Questions & Answers

how can chip be made from sand
Eke Reply
is this allso about nanoscale material
Almas
are nano particles real
Missy Reply
yeah
Joseph
Hello, if I study Physics teacher in bachelor, can I study Nanotechnology in master?
Lale Reply
no can't
Lohitha
where is the latest information on a no technology how can I find it
William
currently
William
where we get a research paper on Nano chemistry....?
Maira Reply
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
Ali
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
Google
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
hey
Giriraj
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
revolt
da
Application of nanotechnology in medicine
has a lot of application modern world
Kamaluddeen
yes
narayan
what is variations in raman spectra for nanomaterials
Jyoti Reply
ya I also want to know the raman spectra
Bhagvanji
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
Privacy Information Security Software Version 1.1a
Good
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply

### Read also:

#### Get Jobilize Job Search Mobile App in your pocket Now!

Source:  OpenStax, Mathematics grade 7. OpenStax CNX. Sep 16, 2009 Download for free at http://cnx.org/content/col11075/1.1
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Mathematics grade 7' conversation and receive update notifications?

 By Brooke Delaney By OpenStax By Madison Christian By By OpenStax By Brooke Delaney By Rylee Minllic By OpenStax By Jill Zerressen By Eddie Unverzagt