Unit 1

NATURAL NUMBERS


number classification

We classify numbers in various groups. The more complex groups contain the simpler groups.

The group of natural numbers only contains natural numbers.

The group of integers contains the natural numbers and the negative numbers.

The group of rational numbers contains integers, fractions and decimals.

We can represent numbers on a “number line”:          111


1        Is number 2 an integer? Why?

2        What type of numbers do we use for:

a)      The age of people?          c)  The portions of pizza?

b)      The temperature?           d)  The floors of a building?

3        Draw a “number line” with numbers from 0 to 5 and put a circle around number 4.

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1.1   What are natural numbers?

A natural number is a number that counts whole entities.

For example 3 tomatoes, 6 chairs, etc.

Two thirds is not a natural number.


1.2   Equalities and Inequalities

A natural number can be less than, equal to, or greater than another.

“Equal to” (=) is the equality.

“Less than” (<) and “greater than” (>) are the inequalities.

“Less than or equal to” (≤) and “greater than or equal to” (≥) are the equalities or inequalities.

=   equal to                               8 = 8

<   less than                              1 < 2

>   greater than                        4 > 3

   less than or equal to         4 ≤ 20

   greater than or equal to     7 ≥ 7


Write:

A number that is equal to 8                      8 = 8

A number that is less than 8                     5 < 8

A number greater than 8                         14 > 8

A number less than or equal to 8             1 ≤ 8

A number greater than or equal to 8       8 ≥ 8

A school bus can carry 55 students.

If we don’t know how many students are on the bus, we can say that:

The number of students on the bus is ≤ 55


1        Which of these numbers are natural numbers?

a)      3                      d)  8                            g)  0                            j)  7

b)      -8                    e)  2                            h)  2/3                         k)  17

c)      2.6                   f)  √6                           i)   25                          l)  -7

2        Which inequalities are correct?

a)      0 > 1                d)  5 ≥ 2                      g)  6 < 8                      j)  8 ≤ 7

b)      9 ≥ 9                e)  41 > 39                  h)  5 ≤ 6                      k)  2 ≥ 1

c)      7 < 12              f)   24 ≤ 25                  i)  1 > 7                                   l)  4 < 5

3        Amelia has ten apples and one orange. Julia has six apples and four oranges. Who has more pieces of fruit? Why?

 

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