Topicmf492d329fd02c5a8_1528449000663_0Topic

Methods of multiplication of natural numbers in memory

Levelmf492d329fd02c5a8_1528449084556_0Level

Second

Core curriculummf492d329fd02c5a8_1528449076687_0Core curriculum

II. Operations on natural numbers. Student:

3) multiplies and divides the natural number by a, one‑digit, two‑digit or three‑digit natural number in writing, in memory (in the simplest examples) and by using a calculator (in more difficult examples);

5) uses convenient methods to facilitate calculations, including the commutative and associative properties of addition and multiplication, and distributive properties of multiplication over addition.

Timingmf492d329fd02c5a8_1528449068082_0Timing

45 minutes

General objectivemf492d329fd02c5a8_1528449523725_0General objective

Performing uncomplicated calculations in memory or in more difficult problems in writing and the use of these skills in practical situations.

Specific objectivesmf492d329fd02c5a8_1528449552113_0Specific objectives

1. Multiplication of natural numbers in memory.

2. Multiplication of natural numbers in memory used to solve word problems.

3. Communicating in English, developing mathematical, scientific, technical and IT competences, developing learning skills.

Learning outcomesmf492d329fd02c5a8_1528450430307_0Learning outcomes

The student:

1. Student uses different methods of multiplication of natural numbers in memory.

2. Student uses the multiplication of natural numbers in memory to solve word problems.

Methodsmf492d329fd02c5a8_1528449534267_0Methods

1. Discussion.

2. Case study.

Forms of workmf492d329fd02c5a8_1528449514617_0Forms of work

1. Group work.

2. Individual work.

Lesson stages

Introductionmf492d329fd02c5a8_1528450127855_0Introduction

Students review their knowledge on how to multiply natural numbersnatural numbersnatural numbers, what we call numbers that we multiply and what we call the result of multiplicationmultiplicationmultiplication.

They present the properties of multiplicationmultiplicationmultiplication and the possibilities of their application.

Proceduremf492d329fd02c5a8_1528446435040_0Procedure

Discussion - students talk about their own methods of multiplicationmultiplicationmultiplication in memory.

Students work individually using computers. They open SLIDESHOW and observe how we can multiply two natural numbers in memory.mf492d329fd02c5a8_1527752263647_0Students work individually using computers. They open SLIDESHOW and observe how we can multiply two natural numbers in memory.

After completing the task, the students present the results of their observations.

[SLIDESHOW]

Students work in groups. Using the acquired knowledge they solve the problems. They compare their solutions, discuss the methods of multiplicationmultiplicationmultiplication used, check the correctness of their solutions. The teacher assesses students’ work.

Task 1 (group 1)

Calculate:mf492d329fd02c5a8_1527752256679_0Calculate:

a) 12 · 6,
b) 4 · 14,
c) 19 · 7,
d) 3 · 18,
e) 15 · 5.

Task 2 (group 2)

Calculate:

a) 15 · 10,
b) 2 · 400 · 6,
c) 73 · 50 · 2,
d) 20 · 16 · 5,
e) 230 · 3,
f) 500 · 3 · 4.

Task 3 (group 3)

Solve the following word problems. Write down all the calculations and solutions.

1. An Indian elephant needs 150 kg of food per day. How many kilos of food do you need to prepare weekly for one elephant?

2. The mother wants to buy a bike for Maciek. She will pay for the bike in 10 installments, PLN 265 each. How much will she pay for his bike?

3. A cinema ticket costs PLN 28. How much do you have to pay for 6 tickets?

Task for volunteersmf492d329fd02c5a8_1527712094602_0Task for volunteers

A cup of yoghurt costs PLN 2. Yoghurts are packed in cartons, in which there are three rows of six cups of yogurt. How much change will the customer receive if he/ she buys two such cartons and pays with a PLN 100 banknote?mf492d329fd02c5a8_1527712094602_0A cup of yoghurt costs PLN 2. Yoghurts are packed in cartons, in which there are three rows of six cups of yogurt. How much change will the customer receive if he/ she buys two such cartons and pays with a PLN 100 banknote?

Lesson summarymf492d329fd02c5a8_1528450119332_0Lesson summary

Students do the revision exercises.

Then they summarize the lesson together, formulating conclusions to remember:

- When multiplying natural numbersnatural numbersnatural numbers you can use associative and commutative properties of multiplicationmultiplicationmultiplication.

- When multiplying in memory, two‑digit factorfactorfactors can be broken down into sumsumsum or productproductproduct and multiplicationmultiplicationmultiplication can be done in stages.

Selected words and expressions used in the lesson plan

factorfactorfactor

multiplicationmultiplicationmultiplication

natural numbersnatural numbersnatural numbers

productproductproduct

sumsumsum