# Connexions

You are here: Home » Content » Mathematics Grade 7 » Adding and subtracting of decimal fractions

### Lenses

What is a lens?

#### Definition of a lens

##### Lenses

A lens is a custom view of the content in the repository. You can think of it as a fancy kind of list that will let you see content through the eyes of organizations and people you trust.

##### What is in a lens?

Lens makers point to materials (modules and collections), creating a guide that includes their own comments and descriptive tags about the content.

##### Who can create a lens?

Any individual member, a community, or a respected organization.

##### What are tags?

Tags are descriptors added by lens makers to help label content, attaching a vocabulary that is meaningful in the context of the lens.

#### In these lenses

• GETSenPhaseMaths

This collection is included inLens: Siyavula: Mathematics (Gr. 7-9)
By: Siyavula

Collection Review Status: In Review

Click the "GETSenPhaseMaths" link to see all content selected in this lens.

Click the tag icon to display tags associated with this content.

### Recently Viewed

This feature requires Javascript to be enabled.

### Tags

(What is a tag?)

These tags come from the endorsement, affiliation, and other lenses that include this content.

Inside Collection (Course):

Course by: Siyavula Uploaders. E-mail the author

# Adding and subtracting of decimal fractions

Module by: Siyavula Uploaders. E-mail the author

## Memorandum

17.2 a) 999,955

1. a) 802,383
2. b) 115,749
3. c) 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

## Content

### 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:
Table 1
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.

## Content actions

EPUB (?)

### What is an EPUB file?

EPUB is an electronic book format that can be read on a variety of mobile devices.

PDF | EPUB (?)

### What is an EPUB file?

EPUB is an electronic book format that can be read on a variety of mobile devices.

#### Collection to:

My Favorites (?)

'My Favorites' is a special kind of lens which you can use to bookmark modules and collections. 'My Favorites' can only be seen by you, and collections saved in 'My Favorites' can remember the last module you were on. You need an account to use 'My Favorites'.

| A lens I own (?)

#### Definition of a lens

##### Lenses

A lens is a custom view of the content in the repository. You can think of it as a fancy kind of list that will let you see content through the eyes of organizations and people you trust.

##### What is in a lens?

Lens makers point to materials (modules and collections), creating a guide that includes their own comments and descriptive tags about the content.

##### Who can create a lens?

Any individual member, a community, or a respected organization.

##### What are tags?

Tags are descriptors added by lens makers to help label content, attaching a vocabulary that is meaningful in the context of the lens.

| External bookmarks

#### Module to:

My Favorites (?)

'My Favorites' is a special kind of lens which you can use to bookmark modules and collections. 'My Favorites' can only be seen by you, and collections saved in 'My Favorites' can remember the last module you were on. You need an account to use 'My Favorites'.

| A lens I own (?)

#### Definition of a lens

##### Lenses

A lens is a custom view of the content in the repository. You can think of it as a fancy kind of list that will let you see content through the eyes of organizations and people you trust.

##### What is in a lens?

Lens makers point to materials (modules and collections), creating a guide that includes their own comments and descriptive tags about the content.

##### Who can create a lens?

Any individual member, a community, or a respected organization.

##### What are tags?

Tags are descriptors added by lens makers to help label content, attaching a vocabulary that is meaningful in the context of the lens.

| External bookmarks