2.1 Division  (Page 2/5)

3. Now let us see what happens when we divide any number by 0. Work with a friend once more and do the following with the aid of your calculator:

3.1 6 ÷ 0 = ................................... 3.2 38 ÷ 0 = ..............................

3.3 438 ÷ 0 = ............................... 3.4 1 679 ÷ 0 = .........................

• 63 827 ÷ 0 = .........................

4. Why does the calculator give these answers?

DO YOU STILL REMEMBER?

Division by 0 is not allowed. We say it is undefined .

BRAIN-TEASER!

I think of a number. If I subtract 3 and then divide the number by 6, the quotient will be 7. What is the number? ..................

I think of another number. If I halve it and then divide it by 12, the quotient will be 9. What is the number? ..................

Activity 4:

To describe and illustrate other cultures' ways of writing [lo 1.2]

DID YOU KNOW?

The Chinese write either from top to bottom or from left to right. Some of their numbers look like these:

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

100.

1.1 Can you write the following in Chinese? Then give the answer in our number system.

Division by 10, 100 and 1 000

Activity 5:

To describe observed patterns and rules in own terms [lo 2.2]

1. In Mathematics certain rules enable us to calculate answers quickly. However, we must be able to "spot" or "deduce" the rule first before we can apply it. Work with a friend and complete the table.

What do you notice when you look at the answer?

2. Complete the following also:

Can you also write down the answers to the following?

3. Can you also write down the answers to the following?

What happens when we divide by 1 000?

Division by multiples of 10 and 100:

Activity 6:

To calculate by using selected computations [lo 1.8.4]

1. You have now discovered rules for division by 10, 100 and 1 000. Now let us look at division by multiples of 10 and 100. Work through the following calculations with a friend:

2. Complete the following on your own:

2.1 1 380 ÷ 60 = (1 380 ÷ 10) ÷ ..................

= .................. ÷ ..................

= ..................

2.2 32 840 ÷ 40 = (32 840 ÷ ..................) ÷ ..................

= ......................... ÷ ..................

= ..................

2.3 15 500 ÷ 500 = (15 500 ÷ 100) ÷ ..................

= .................. ÷ ..................

= ..................

2.4 312 300 ÷ 300 = (312 300 ÷ ..................) ÷ ..................