4.10 Adding and subtracting

Mathematics

Mathematics in the world around us

Educator section

Memorandum

Critical and developmental outcomes:

The learners must be able to:

1. identify and solve problems and make decisions using critical and creative thinking;

2. work effectively with others as members of a team, group, organisation and community;

3. organise and manage themselves and their activities responsibly and effectively;

4. collect, analyse, organise and critically evaluate information;

5. communicate effectively using visual, symbolic and/or language skills in various modes;

6. use science and technology effectively and critically, showing responsibility towards the environment and the health of others;

6. demonstrate an understanding of the world as a set of related systems by recognising that problem-solving contexts do not exist in isolation;

7. reflect on and explore a variety of strategies to learn more effectively;

8. participate as responsible citizens in the life of local, national, and global communities;

9. be culturally and aesthetically sensitive across a range of social contexts;

10. explore education and career opportunities; and

develop entrepreneurial opportunities.

• Integration of Themes:
• Social justice: The story of the secret signs shows how history can be important. What are the advantages of knowing things about the past?

Learners can divide into groups, visit the library and do more research on the origin of our number system, the Roman numerals, etc.

Learners can do projects on Mathematics found in nature, in the classroom and in the home. They learn to work together in a team, listen to one another and to share ideas.

Discuss whether so called “bargains” are always bargains. What is your attitude towards “sales” in shops? Is it always necessary to give / receive birthday presents? Why do you give presents? When would not giving presents be acceptable?

• With the inclusion of the story of the secret sign at this stage, learners are able to understand the significance of the “0” as “place holder” (indegrated with Literacy).
• The patterns with addition and subtraction of 6, 7, 8 and 9 are emphasised.
• Telling the time in minutes become easy as learners count the minutes in 5’s.
• Codes are used to find the answer to a puzzle.
• As preparation for the Christmas celebrations, the month of December is used for activities involving the calendar.
• Module 8 concludes with a game where crackers with number sentences are matched to lights on the Christmas tree.

Leaner section

Content

ACTIVITY: Adding and subtracting [LO 1.6, LO 1.10, LO 1.11]

• Read these advertisements. Complete them.

• My friends went shopping for bargains (see p. 20). Tell a friend how you got the answer.
• Voltooi:

1. Mo bought 5 ping pong balls for ...... c and one fishing net for ......c.

She paid ...... ...... = ......c

2. Bob bought 4 beach bats for R ...... and 1 pair of goggles for R ......

He paid R ...... + R ...... = ......

3. Mom gave Des R1 to buy diving sticks.

He bought ...... diving sticks for ...... c.

He took ...... change home.

4. Tom paid R ...... for 2 beach balls. He also bought 5 ping pong balls for ...... c.

He paid R ...... + ...... c. = ......

5. What will 3 pairs of goggles cost if the price is R30 for 1 pair? ....…………………………

• Here is a present for you.
• Write the answers of the number sentences to find out what the code is for:

A = ____________

B = ____________

C = ____________

D = ____________

E = ____________

F = ____________

G = ____________

H = ____________

I = ____________

J = ____________

K = ____________

L = ____________

A 36 + 5 = ____________

B 28 - 3 = ____________

C 94 - 3 = ____________

D 9 + 8 = ____________

E 17 - 7 = ____________

F 12 + 12 = ____________

G 6 + 6 + 6 = ____________

H 6 x 2 = ____________

I 3 x 3 = ____________

J 67 - 5 = ____________

K 50 + 20 = ____________

L 88 - 80 = ____________

• Use the code to find out what is in the box.

Code: 25, 41, 8, 8

Answer: ......

• Check with a friend to see what he found in the box.

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 1.6: We know this when the learner solves money problems involving totals and change in rand and cents;

Assessment Standard 1.10: We know this when the learner uses the following techniques:

1.10.1 building up and breaking down numbers;

1.10.2 doubling and halving;

1.10.3 number-lines;

1.10.4 rounding off in tens.

Assessment Standard 1.11: We know this when the learner explains own solutions to problems;