Lesson 1 – Doubles And Halves

Objective:

• At the end of this lesson, students should be able to double numbers and halve even numbers.

When we talk about halves (Half =1/2), we are talking about sharing or dividing objects or items into two equal parts e.g.  1/2 of 2 = 1

This means that sharing 2 or dividing 2 into equal parts will give us one (1).

ALSO

1/2 of 6 = 3                 AND               1/2  of 4 = 2

In the same way, we can say that the opposite of sharing or dividing by 2 is doubling. Doubling is multiplying a number by 2 or adding a number to itself.

E.g. Double 2 = 4

Double 2 can be written as     2 x 2 = 4                   OR              2 + 2 = 4

Double 3 = 6            i.e         2 x 3 = 6                         OR           3 + 3 = 6

We can therefore conclude that the opposite of halving is doubling. Therefore:

1/2 of 8 = 4                   4 x 2 = 8           and              4 + 4 = 8